Comptia 1101 Flashcards
Which laptop feature allows users to overcome standard limitations of the keyboard?
Fn key
Which of the answers tecers to internal data storage devices used in laptops
SSDs and magnetic disks
Magnetic drives have what features
High capacity, low cost, low performance
SSDs have what features
Relatively high cost, lower capacity, high performance
Which would be the hardest to replace on a laptop?
Integrated GPU
What type of cards enables communication in 802.11 networks?
WLAN
What is a laptops Bluetooth module an example of?
WPAN
What type of expansion card enables communication over a cellular network
WWAN card
What are the characteristics of IPS LCDs?
High color quality, wide viewing angles, slow response times
What are the characteristics of TN LCDs
Low viewing angles, fast response times, high color quality
What are the characteristics of VA LCDs
High contrast ratios, good viewing angles, good color quality
What are the characteristics of OLEDs
Works without backlight, lower light output than LCDs, better contrast and color representation than LCDs
What is the function of a digitizer
Translate analog data to computer format, component of a mobile device that allows you to touch the screen, a type of input device
What is the function of a laptop’s inverter
Converts AC to DC power, converts DC to AC power, supplies voltage to backlights on older LCDs
Riser card
An expansion card to extend a slot to make it easier for a chip to plug in; a custom small motherboard/expansion for audio, visual, modem, etc.
Do lithium ion batteries have a memory effect?
No
What is a SO-DIMM
Small Outline Dual Inline Memory Module is a very common form factor for extra memory on laptops, and there’s often a dedicated panel for it. Without a SO-DIMM, you would have to replace the entire laptop motherboard to Urías m upgrade memory
What size are magnetic disk drives?
2.5”
Mini PCI and mini PCIe
Interfaces that allow additional connectivity
CCFLs
Cold Cathode Flourescent Lamps, backlight on older laptops.
Common backlight troubleshooting tip
If you can shine a flashlight and make out the screen, the backlight is the problem
Different types of USBs
Usb a- most common
Mini b- older
Micro b- newer
Usb c- 24 pin double sided pin can send displayport and hdmi
Lightning- proprietary 8pin apple connection
DB-9
Older connection used to send rs232, used since 1969, also commonly used on modems and mouse
Different writing devices
Touch screen pens/capacitive stylus is good for precise writing
Digital soles is more advanced, Can communicate when not touching, also pressure sensitive (BRAND SPECIFIC)
External digitizer/ drawing pad an active stylus that can connect to many different brands
2G
2G consists of GSM (global system for mobile communication) and CDMA (Code Division for Multiple Access)
It has voice communication but little data transfer.
GSM included 90% of worldwide market, At&t etc.
CDMA allowed different people on the same network by assigning codes (Verizon and Sprint)
SIM
Subscribe Identification Module allows one customer to use different devices
3G
3G allowed for more data, more speed, better functionality, GPS, streaming, and video on demand
4G
LTE (long term evolution), based on GSM and edge?
LTE advanced, or LTEA doubled the throughput
5G
Will go up to 10 gbps, its best for IoT devices, faster data, more cloud space,
Will have slower speeds of 100-900 mbps???
GPS
GPS comes from at least 30 satellites, and has to connect to at least 4 satellites
MDM
Mobile Device Management allows to partition a phone for work and personal use
Ethernet Payload
IP header & IP payload
TCP header and TCP payload
HTTP payload
Multiplexing
Using many different applications to talk to many different servers at the same time
TCP
Transmission Control Protocol is a connection based protocol, it sets up and breaks down payload and utilizes reliable delivery (verification of received data), and can request slower or faster data speed
UDP
Unreliable delivery, no confirmation of received data, no flow control, think Voip, FaceTime, etc.
FTP
Active mode TCP21
Control TCP20
Telnet
Telecommunications offers unecrypted remote access
TCP 23
SMTP
Simple mail transfer protocol
TCP25
DNS
Domain name service UDP 53, assigned ip address
DHCP
Dynamic Host Configuration Protocol udp 67 and 68
Automatically configure and reserve ip address, subnet mask, and more everything is assigned in real time and renew at set intervals
Pop3
Post office protocol 3 TCP 110
Used for basic mail transfer
Imap
TCP143
Internet Message Access Protocol 4
allows different devices
SMB
Server Message Block
Used by windows for file sharing/printer sharing
AKA CIFS (Common Internet File System)
NETBIOS
Network Basic Input Output System
(Older)
UDP137 (nbname)
UDP139 (nbsession)
SNMP
Simple Network Management Protocol
Gathers network statistics
UDP161 for queries
UDP162 for traps
V1 was just structured tables
V2 was bulk transfers
V3 was encrypted
Lightweight Directory Active Protocol
Fast network directory, e.g Microsoft access directory
RDP
Remote Desktop Protocol
TCP3389
May vary on windows versions
Can control an entire system or a single computer
Routers
Layer 3 devices that forward data based off IP ADDRESS, SoHo routers are also access points
Switches
Switches are layer 3? Devices that send data based on destination Mac Address, switches can move faster because they have Application Specific Integrated Circuit (ASIC), switches have PoE
Managed Switches
Managed switches have vlans (subnets), SNMP, you can prioritize traffic, and have redundancy protection through Spanning Tree Protocol (STP) and port mirroring
Access points
Area bridge from the wired network to the wireless network, is not the same thing as a router. It makes forwarding decisions based on the MAC address
Cable Infrastructure
From the desk to patch panel is typically permanent. On the other side of the panel, RJ45s extend to the switch that goes all the way to the main network
PoE
Can be endspan or midspan and 802.11 come with PoE capabilities, switches will identify what Can and can’t support PoE(blue line on top) and UPLINKS DON’T REQUIRE POE
PoE IEEE 802.3af-2003
the original PoE Ethernet standard
15.4 watts DC, 350 mA max current
PoE+ IEEE 802.3at-2009
25.5 watts DC, 600 mA max current
PoE++ IEEE 802.3bt-2018
Type 3: 51 W, 600 mA max current
Type 4: 71.3 W, 960 mA max current (10gbps speeds)
Hubs
Multi port repeater, not smart, can’t run full duplex, only sold at 10 mb or 100 mb, not common today
Cable Modem
Broadband allows multiple frequencies of traffic, like video, voice, and internet.
Data is transmitted via DOCSIS, data speeds top out at 1 gbps
DSL
Asymmetrical digital subscriber line (downloads faster than upload)
There’s a10,000 ft distance limitation
52mbps download, 16 mbps upload
(Faster if closer to the source)
ONT
Optical Network Terminals take fiber optic abs translate it to copper signals
Demarcation Point
Where your stuff ends and the providers stuff begins
Network interface cards
Copper (ethernet) connections use NICs, are built into consumer products, and they are specific to the network type. They can be built into the motherboard, or added as an expansion card.
Single port, multiport, copper, abs fiber options are available
What are the 3 planes of software defined networking?
Infrastructure/data Layer???
Control Layer???
Application/mgmt layer???
Infrastructure/data layer
forwards, trunks, encrypts, NAT
Control Layer
for references, routing protocol NAT table
Application/mgmt layer
configures and manages the device, (SSH, Browser, API, etc.)
802.11a
Made in 1999, exclusively 5Ghz, but Can other frequencies with special licensing. 54 mbps. Smaller range than 802.11b, best for warehouse etc. (absorption issues)
802.11b
Made in 1999, runs at 2.4 Ghz, 11mbps, but less absorption problems. Better for office use.
802.11g
June 2003, 54mbps at 2.4ghz, backwards compatible with 11b, still has frequency issues
802.11n
2009 (wifi4) both 5 and 2.4 ghz 40 mhz Channel widths, greater bandwidth for bigger data transfers, 600mbps, MIMO (multi input, multi output)
802.11ac
January 2014 (wifi5) only at 5 Ghz, up to 160 mhz bandwith, signaling modulation (increases bandwith), 8 MU-MIMO (multi user mimo), double streams at nearly 7gbps
If an access point uses 2.4, the 867 mbps for 8 streams, or 6.9 gbps (802.11n)
8 downloadable streams
OFDMA
Orthogonal Frequency Division Multiple Access works similar to cellular networks to improve in high density areas
802.11ax
February2021 (wifi6)5 and/or 2.4 ghz 20,40,80,or160 mhz bandwidths, 1.1201 mbps per channel, 9.6 gbps total (resolves overcrowding)
Download and upload streams simultaneously
Where do wireless standards come from?
IEEE LAN/MAN standards committee
(IEEE 802)
What is the range of wireless access points in a home setting?
40-50 feet
RFID
Radio Frequency Identification, commonly used in id badges, pet tracking, inventory/assembly, etc., also includes NFC and pairing Bluetooth
there’s not usually a battery
Channel
A group of frequencies
5 ghz range
???
36-177
Bluetooth channel
ISM (industrial, scientific, medical)
Distance is usually 10 meters, although some industrial standards hit 100 meters
DNS server
Converts domain names to ip addresses and Vice versa, there are multiple for redundancy
DHCP server
Provides IP addresses to devices. In an enterprise there will be redundancy
File Server
Centralized storage device which uses SMB (windows) or AFP (Apple File Protocol)
Print Server
Allows any computer to access any printer/scanner, sometimes the software for print sharing is on the computer
Mail Server
Requires 100% up time and availability. There are cloud based options with dedicated support
Syslog
Each server makes logs, syslog is a centralized database of server logs which requires a lot of storage. SIEM???
Web Servers
Uses http(s) protocols to transfer html files. Web pages are stored on the server and Can be built dynamically??? Or static
Authentication Server
Stores all passwords, must be readily available and redundant
UTM
Unified Threat Management:
Detects malware and spam as a router. Can provide intrusion detection, you can prioritize traffic, and use it as a VPN
Load Balancers
Checks in with all servers in case one goes down. Can change the way protocols work, Can encrypt and decrypt, Can cache for a faster response, content switching
Content switching
Putting certain applications on certain servers
SCADA/ICS
Supervisory Control And Data Acquisition system is a kind of Industrial Control System which provides real time info and system controls for multi site industrial applications. Requires permissions and segmentation (Downtime is COSTLY)
Embedded Systems
A purpose built device that only allows certain access, mfr provides support
IoT
May require segmentation to limit security breaches. (SEGMENTATION AS SECURITY???)
IPv4
Ipv4 is 4 bytes (32 bits/4 octets) each separated by a period
255 is the max number of numbers that fit in a byte
IPv6
4 octets separated by colons, first 64 bits is the network prefix and last 64 bits is the host address. DNS is important because addresses are more complicated
Subnet Mask
The subnet mask is not transmitted, it masks everything but the host address.
What are the two things you need to assign an ip address
Subnet mask, ??????
Default Gateway
Default gateway is a router that allows you to communicate outside of your subnet mask. The default gateway IP must be on your subnet mask.
Where can DNS be configured?
Inside the OS under IP settings, setup 2 servers for redundancy
BOOTP
BOOTP was used until 1993. It required ip addresses to be manually configured and couldn’t recognize when ip addresses were free again.
DHCP
Made in 1997, automatically assigned IP, subnet mask, default gateway, etc.
4 step program utilized by DHCP
DORA:
Discover
Offer
Request
Acknowledge
What kind of broadcasts are not blocked by some routers? (Proxy/relay, AKA IP helper)
DHCP broadcasts
UDP 67 and 68
DHCP Broadcasts and responses
What is the best practices for when you want a device to keep its IP address
DHCP reservations,
Alternatively, you could disable DHCP and configure manually, but you gotta reconfigure whenever the network changes.
APIPA
Automatic Private IP Addressing
There’s no forwarding by routers, so you can’t communicate outside your subnet mask
APIPA range: 169.254.0.1 to 169.254.255.254
Who decides a device’s APIPA?
The device itself
ARP
Address Resolution Protocol
What are some examples of a fully qualified domain?
.comi .net
How many top level domain names (TLDs) are there?
Hundreds
How many root clusters servers are there?
13
Cmd dig or nslookup
Looks up IP associated with a given website
How many types of resource records do they have for DNS?
Over 30 (ip, domain, certificates, etc.), and they’re very important.
Many DNS configuration files are what type of document?
Plain text html, but some DNS server provide web based front ends
Start of authority record includes:
mail exchanger record, list of ip addresses, fully qualified domain names, canonical (alias) names
What is an address record
a record, or quad a record: defines the host ip address. Quad a record has ipv6 and fully qualified domain name.
Time To Live:
how long the device will remember the address record without asking the server again.
Mail exchange record
these are names only, if you want the ip for the mail server, pull up the a record
What does a DNS server store TXT records for?
The TXT record might verify the origination, or give configuration details???
SPF record (sender policy framework)-
mail servers query the dns server, retrieve the SPF record and determine if its authentic
DKIM
Domain keys identified mail, a digital signature to verify mail, the public key is the DKIM in the DNS server.
DMARC???
domain-based authentication, reporting, and conformance- You can specify to the mail server whether to keep, throw away, or send to spam if the message isn’t validated. The mail server remembers how many messages were received and you can use DMARC to figure out how much mail got through based on the configuration???
DHCP Scope properties:
IP address range(and excludes ip addresses), subnet mask, lease duration
Other DHCP scope options:
DNS server settings, default gateway, VOIP servers (specify the gateway so that all the voip devices know who to contact)
DHCP pools:
grouping of IP addresses, e.g 192.168.1.0/24
Typically DHCP pools are contiguous, sometimes there are excluded addresses
Can DHCP be on a router?
Yes
Dynamic assignment:
assigns IP based on what’s available, keeps track of expired leases
Automatic assignment:
remembers who connected prior and give the same ip address if possible
DHCP address allocation:
aka static DHCP assignment, aka ip reservation, save a spot based on MAC address,
T1 lease countdown:
T1 timer checks in halfway through the DHCP and resets to full lease time. If the DHCP is unavailable, then the lease continues to countdown.
T2 lease countdown
T2 goes off at 7/8ths and checks in to DHCP
What is a LAN
Local area networks are a group of devices on the same broadcast domain
What’s the best way to run two LANs
For efficiency, multiple switches are not best practice. 1 Switch manages 2 broadcast domains from a VLAN.
VPNs:
software and hardware combo that allows you to encrypt data that’s traversing a public network
Concentrator:
the encrypt/decrypt mechanism can be configured into a firewall or a standalone device
How does data traffic flow on a VPN?
VPNs go from laptop, through internet, to concentrator, then to corporate network, then back again
Satellite Connections
Satellite/non terrestrial is expensive
50mb/s going down, 3 mb/s going up is common
Satellite latency
Latency can be up to 250 ms, very slow
Starlink gives 40 ms, working on 20 ms
They operate over higher frequencies like 2GHz and operate over line of sight, rain can hurt the signal
Fiber Optic Internet Connection:
Very fast, can communicate over long distances, but it’s very expensive
Fiber optics is the WAN core, but it’s expanding to the home/office as well
What is broadband?
Broadband allows multiple connections bydifferent frequencies on the same line
DOCSIS-
data over cable service internet spec,
50mbps - 1k+mbps are common
DSL::
Use the existing telephone lines to provide internet
10,000 foot limit with DSL
Wireless Internet Service Provider (WISP):
Terrestrial internet access points in a general area
Usually in rural areas
Uses meshed 802.11, 5g, or proprietary wireless connection
You’ll need an outdoor antenna
Can operate at speeds of 1k mbps
Local Area Network:
a building or a group of buildings, LANs use 802.11 and Ethernet. If it’s any slower, it isn’t a true LAN
Wide Area Networks:
span the globe, they generally connect LANs across great distances. Great distances mean slower speeds
Are WAN and LAN technologies similar?
No, WAN technologies are different than LAN (point to point serial???, MPLS???, etc)
WAN includes satellite
Personal Area Networks:
Bluetooth, NFC etc.
Metropolitan Area Network (man):
City wide network, not a LAN or MAN
Today, Metro Ethernet is popular (you get Ethernet on both sides and then an ISP connects them
Governments use them primarily because they have the right of way to put conduit in the ground
Storage Area Network:
A high speed network that allows to connect to a very large storage facility,
Provides block level access which makes it more efficient to read and write
Requires high bandwidths to retrieve and send
Often isolated on its own high speed network
WLAN:
Doesn’t reach very far
Can be extended with more access points
Cable Crimpers::
Pinch the cable on the wire
Coax, twisted pair, and fiber crimpers are available
Twisted pair crimp through the insulation and into the wire itself
Can you mix different Cat crimpers and wires?
No, Cat5,6,&7 cables have to go into corresponding crimpers
Modular Connectors::
End pieces for rj45 connectors
Cable must run to the top of the rj45
Tone Generators and Probe
Tone generator creates a tone on copper wire, probe detect tone, probe is inductive, so it doesn’t need to touch
Punch Down Best Practices:
Specialized tools to punch each wire into the punch down block
Organization is key (cable management)
Maintain the cable twist, and document what you did
Cable Testers:
Performs continuity tests to see if pins are properly aligned, Can tell you if you’ve missed or crossed wires
Cannot identify signal loss, crosstalk, etc.
TDR (time domain reflectometer)???
Loopback Plugs:
Plug that loops back into itself, useful for testing ports
You can get loopback plugs for fiber, ethernet, t1, etc.
Taps and Port Mirrors:
Physical network tap allows you to disconnect in the middle and put a tap that sends the data to an analyzer
Active taps:
Active taps can tap copper but they require power
SPANs
Port mirrors, or SPANs (switch port analyzers) Can be built into your switch
SPANs are software that sends data to a second interface that you can send to an analyzer.
Has bandwith limitations, but SPANs are a great short term option
Protocol analyzer/monitor???
Look it up
TWISTED PAIR COPPER CABLING
Most Common Ethernet Connection
Each pair sends opposite signals
Twisted cables twist away from interference. Combining 2 cables helps prevent interference
Cables are twisted at different intervals
What are the 4 pairs of twisted pair cabling?
Blue,blue/white, orange, orange/white, solid green, green/white, solid brown, brown/white
COAXIAL CABLES
Two or more forms sharing one axis
(metal wrapped around an insulator with metal rod, often used with RG6
PLENUM RATED CABLES
Plenum is a part of the air conditioning
In case of fire, plenum rated cables won’t smoke up. They’re usually more stiff.
SHIELDED AND UNSHIELDED CABLE RATINGS
U-unshielded
S-braided shielding
F-foil shielding
Ex. S/FTP
Braided around the entire cable, foil around the pairs
Ex. F/UTP
Foil around the entire, nothing around pair
DIRECT BURIAL STP CROSS SECTION
Overhead may not be best, Direct Burial STP for shielded twiisted pair
Sometimes they require no conduit
THey utilize waterproof gel, and a ground wire (AKA drain wire) to take away any additional voltages.
Optical fiber:
No radio frequencies, they can go much further than twisted pair.
No interference from other radio frequencies
The fiber itself is very small, surrounded by absorbent cladding and protective layer
Multimode
Multimode works up to 2km, uses inexpensive light source.
Multimode is large enough for multiple reflections to occur as light moves through fiber.
Single mode
Single mode is much smaller, goes 100km+, uses lasers instead of LED
Who defines network standards
The International ISO standard defines network standards
Who defines cabling standards
Telecommunications Industry Association TIA
ANSI/TIA-568 commercial building telecomms cabling standard
Who uses T568B?
End users often use T568B
Who sets standards for Ethernet crossover cables
Check IEEE standards for ethernet crossover cables
Which Piña are common in T568 A and B
Pins 4,5,7,& 8 are all the same in 568a and 568b
Many punch down blocks have guides for A and B.
USB 1.1
USB 1.1 low speed was 1.5mbps up to 3m, high speed was 12mbps up to 5m
USB2,0
USB2,0 was 480 mbps up to 5m
USB3.0
USB3.0(superspeed) 5 gigabits/s over 3m, (No specified max cale length
Types of usb connections
Standard A plug (regular plugs into comp)
Standard B plug (cricket plug)
Mini B plug (old cell phone, fat
Micro (regular phone)
Which usb
Standard b and micro b now have the extra slot, but standard A is still the same
USBC
The latest iteration, no A/B connection
Supespeed+ (USB 3.1 gen2) doubles the max speed to 10GBPS
USB3.2
USB3.2 utilizes an extra lane and doubles speed??
USB3.0 has become USB 3.2 gen 1(single lane)
USB3,2 gen 1&2
USB 3.2 gen1x2 uses 2 gen 1 lanes
USB 3.2 gen2x2 uses 2 gen 2 lanes
THUNDERBOLT
HIgh speed serial connector that can put data and power on the same connector
Thunderbolt is based on the Mini DisplayPort (MDP) standard
THunderbolt v1
THunderbolt v1 is a two channel technology. 10gbps per channel, 20 gbps total
Thunderbolt V2
Thunderbolt V2 has an aggregate 20 gbps combined from both V1 channels (mini display port)
THUNDERBOLT V3
USBC connector allows to double the thunderbolt V2 channels and now max spee is 40 GBPS
Max cable length of 3 meters (copper) and 60 meters (fiber)
You can daisy chain up to 6 devices
VGA
VGA is an analog device, not digital and image quality deteriorates after 5-10 meters
15 pins can be assumed to be VGA
VGA is video only, you need another way to get sound when using VGA
THe blue color is specified by the PC System Design Guide
HDMI
HDMI (hi def multimedia interface)
Video and audio
20 meters before dropout and DIGITAL ARTIFACTS appear on screen
19 pin type a connector (exclusive to HDMI)
DisplayPORT
DisplayPort sends info in packeted form like ethernet and PCIe, carries audio and visual signals
Mini displayport
Mini displayport (Like thunderbolt v1), and displayport (almost looks like a usb) hooks lock in a display port so you gotta press a release button.
Displayport and HDMI are compatible
DVI
DVI DIGITAL VIDEO INTERFACE
Single link (3.7gbps)(60fps) and dual link (7.4 gbps)(85fps)
DVI doesn’t pass any audio support
Analog vs digital DVI
DVI-A is analog (dice)
DVI-D is Digital (grid)
DVI-I is integrated (Grid+Dice)
SATA DEVICE CABLES
(SERIAL AT ATTACHMENT)
SATA revision 1.0 1.5 gbps,1m
SATA revision 2.0 3 gbps, 1m
SATA revision 3.0 6 gbps,1m
SATA revision 3.2 16 gbps, 1m
eSATA(external SATA) matches sata version up to 2 meters
SATA facts
SATA has a single connection, powering a singe device.
SATA goes directly from motherboard to STORAGE devices
eSATA use the same standard, but eSATA is very different connector, can’t mix
SCSI
(Scuzi) Standard INterface for scanners, printers, etc.
SCSI can Daisy chain multiple peripherals (up to 16)
Many different SCSI Standards
SCSI 2
SCSI is not just for hard drives, but also tape drives, CD ROMs, Scanners, etc.
You can have many different devices on one bus.
SCSI is very intelligent, it handles the how of accessing the peripherals.
SCSI has much support because it’s been around so long
SCSI 3
There are many types of SCSI connectors
Every SCSI device has a separate ID number on the bus
Logical Units are defined within each SCSI ID to store drives for the peripherals
SCSI terminator should be at the end
Serial attached SCSI (SAS) have no jumpers, terminators, or settings
Serial Attached SCSI
Serial attached SCSI (SAS) have no jumpers, terminators, or settings
The move from parallel to serial SCSI increased throughput and simplified implementation.
There was no more need to daisy chain or terminator, instead it was a point to point connection
PATA name
The AT in pata and sata comes from the AT attachment standard one of the original computers from IBM,
PATA was originally called IDE integrated Drive Electronic
40 wire vs. 80 wire PATA
On a 40 wire PATA cable the first device is 0 and the last device is device 1. These are switched for an 80 wire connection
80 wires helped decrease crosstalk with higher speeds.
How do you know if your PATA is properly connected?
A missing pin and notches help orient the PATA connection
The storage device connector is identical to the motherboard connector
HDMI is compatible with which DVI?
DVI-D is electrically compatible with HDMI, so you only need to switch the connector.
DVI-A is compatible with ______
DVI-A is electrically compatible with VGA, but you can only get 640x480 resolution
What if your laptop doesn’t have Ethernet?
you can get a USB to ethernet connection
RJ11 CONNECTORS
RJ11 connectors have 6 positions and 2 connectors (6P2C), and they are used for telephone and DSL modems
RJ45 CONNECTORS
RJ45 is (Registered jack type 45)
8position, 8connector (8p8c)
Modular connector, used for ethernet
RJ 11 has different shape than RJ 45
F CONNECTORS
Cable connector (coax)
Internet connector (DOCSIS) (data over cable service interface spec)
PUNCHDOWN BLOCKS
Wire to wire patch panel
Permanently attach wires to wiring block
USB1.1/ 2.0 CONNECTORS
A is common, B is common for peripherals, mini and micro more for mobile devices
MOLEX CONNECTORS
4 pin power connector, (AMP mate n lock)
Provides 12v and 5v
LIGHTNING CONNECTORS
8 pin digital signal, proprietary apple tech
DB-9 CONNECTORS
DB-9 are still commonly used in infrastructure devices with console connections
Commonly used to send RS-232 standards
LC CONNECTOR (LOCAL CONNECTOR)
single connector with 2 fibers, 1 to transmit, and one to receive
ST (STRAIGHT TIP) CONNECTORS
locks in with a quarter turn (fiber)
SC (Subscriber/square connector)
often come in pairs, but they can be broken apart for separate runs.
DDR3,4,&5
DDR3 increased data rates to twice as fast, maximum Ram of 16gb
DDR4 increases speed and max memory of a single module to 64gb
DDR5 maxes out at 64, but it has a larger throughput
DIMM DUAL INLINE MEMORY MODULE
DIMM is the standardized memory module for RAM. One side is different than the other, hence DUAL
64bit data widths are a common spec
SODIMM (SMALL OUTLINE DIMM)
SODIMM (SMALL OUTLINE DIMM)
About half the size, common for laptops
Sodimms are often horizontal??
Dynamic Ram (DRAM)
Dynamic Ram (DRAM) has to constantly be refreshed, so it always needs power. Because it’s random, you can recall any piece of information you need (unlike magnetic tape)
CLOCK
Synchronous DRAM, or SDRAM is in sync with a clock
NOTCHES
NOTCHES
The notches prevent using incompatible ddr
Double data rate (DDR)
allows you to transfer double the data as a single data rate
VIRTUAL MEMORY???
Virtual ram, swap file etc. allows you to swap unused app data to storage. This is TEMPORARY
MULTICHANNEL MEMORY
Dual, triple, or quad channel splits the throughput to multiple memory modules. Ideally, you would have the exact same memory in each slot
ERRORS
Memory can check itself for critical compute systems (virtual machines, databases, etc.
PARITY
Adds an additional bit, but it can’t always detect errors and won’t self correct (Even parity will add a bit to odd bytes to make all bits even, if something didn’t add up, data is corrupted)
HDD
Non volatile (can turn off and on)
Random, don’t need to rewind tape
Mechanical components limit speed
All HDDs eventually fail
HEAD AND PLATTER SPEEDS
The faster the drive spins, the lower the latency (HDDs can have multiple heads and platters as well)
5400 rpm - 5.55 ms
7200 rpm - 4.16 ms
10,000 rpm - 3 ms
15,000 rpm - 2 ms
SSD
Is also non volatile (can turn on and off)
There’s no moving parts so no worry aboutmechanical breakdowns
Much faster than HDDs
2.5 SATA INTERFACES
The interface is very important for an SSD, Sata and SSDs are sometimes interchangeable
mSATA
Smaller and more common in mobile devices and laptops, no spinning pieces.
mSATA drives were quickly replaced by M.2 drives
AHCI vs NVMe
Advanced Host Controller Interface (AHCI) is used by SATA to move hard drive data to ram
SSD can be much faster than SATA, so something else was needed.
NVMe
(Non Volatile Memory express) is designed for SSD speeds. You need to use an M.2 interface for this.
M.2 INTERFACE
Smaller form factor, no wires for power or data, higher throughput. Sata revision 3 might be 600gbps, nvme can be 4gbps with NVMe PCIe x4
M.2 keys
There’s different kinds of keys for M.2. There’s aB key and aM key
Flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory)
This is non volatile memory (i.e flash drives don’t need power to save)
There’s a limited amount of times you can wire information to a flash drive. After that point, you should be able to read the information but you will not be able to write any more info
RAID
Redundant Array of Inexpensive/Independant Disks
Some RAID levels give redundancy, some don’t
RAID 0 (Striping)
2 drives, take all of your data and split it (stripe it) evenly between disks.
This provides performance increase, but if you lose anything , you’ve lost everything
Raid 0 means 0 redundancy
RAID 1 (MIRRORING)
Duplicates every single drive for redundancy, but requires twice the storage
RAID 5 STRIPING W/ PARITY
Requires more disks? Split the information and includes parity to piece together the bits from lost drives.
You also want to stagger the parity to different drives
You could lose performance when you have to use parity
RAID 10
(1+0) A STRIPE of MIRRORS . (How many disks needed???)
Standard ATX (Advanced Technology Xtended) Form Factors
A family of motherboard form factors, common in desktops, plenty of real estate for expansion slots and extra stuff
Was standardized in 1995
Power connector is 20, or 24 pins, some have additional power
Mini ITX Form Factors:
Developed by VIA technologies in 2001
screw compatible in ATX
Ideal for small, single purpose computing, e.g streaming
PCI
PCI (Peripheral Component Interconnect) created in 1994
many expansion options, 32 bit and 64 bit bus widths (old, parallel tech)
PCI’s have different voltages as well, there are gaps, or keys that confirm bit width and power rating
PCIe is more common and modern
PCIe uses unidirectional serial lanes
1,2,4,8,16, or 32 full duplex lanes are used (X1,X2,X4, etc. pronounced by1, by2, etc.)
Device A and B have two one way streets to communicate back and forth
DONT PUSH TOO HARD
ATX Motherboard power connectors
was 20pin, switched to 24pin for power.
backwards compatible
Keyed slots ensure proper connection
A Lock prevents plug from slipping out
12v power connectors are used primarily for CPU and may be labeled CPU, P4, or ATX12V
SATA CONNECTORS
are commonly used for hard drives and SSDs (STORAGE)
eSATA connections are a great way to add internal throughput and functionality to external storage devices
HEADERS, or PIN HEADERS:
Groups of pins on the edge of the motherboard,
They might provide power, or USB, or computer buttons, or cooling fans
Computer Buttons are integrated through the motherboard is through connectors provided on the case.
M.2 CONNECTORS
Used to plugin SSD to have all your storage connected to the motherboard.
Intel vs. AMD
You’re locked in once you decide
AMD is cheaper and Intel is stronger.
Laptop motherboards
are usually not built for speed, when it gets too hot, it’ll throttle to prevent damage from overheating.
Laptops have limited modifications.
Laptop system boards are proprietary and custom, so you can’t switch out motherboards like you can with ATX motherboards.
What is the BIOS
Firmware, on ROM or FLASH MEMORY (nowadays, everything is flash, nothing is ROM)
POST-Power On Self Test
is not comprehensive, but checks for memory, CPU, video, and some kind of input (keyboard, mouse, etc.)
Then it looks for a boot drive
Sometimes you have a backup bios so if you upgrade and something goes wrong, you can revert to the previous version.
UEFI BIOS
(Unified Extensible Firmware Interface BIOS), which is based on Intel’s EFI
4 BIOS tabs:
Main, Security, Advanced, UEFI Drivers
How to get to the BIOS
Del, F1, F2, Ctrl-s, Ctrl-Alt-S, etc. during bootup to get to the BIOS settings
Hyper-V (Windows) and VMware Workstation Player allow you to change BIOS settings? (Not Virtualbox)
You can also search for UEFI BIOS simulator??
How to get to BIOS on fast startup
holding shift when clicking restart,
go to settings/update and security/advanced startup/ restart now,
or system config
Or interrupt normal boot system 3 times
BIOS best practices
YOU HAVE TO MAKE A BACKUP OF YOUR BIOS CONFIGURATIONS (write notes, take picture)
BE SURE ABOUT YOUR CHANGES
Versions of windows with fast startup
Windows 8, 10, and 11 have fast startup so you don’t have time to get to BIOS
What can you do in BIOS
You can disable the OS access to hardware from the BIOS
You can tell the BIOS where to boot from (i.e. usb boot drive, ssd, hard drive)
You can modify USB permissions, etc.
Secure boot
SECURE BOOT uses digital signatures to prevent malware from using your boot, it’s stock with UEFI
You can add a boot password for added safety
If you forget password, you gotta reset the BIO
Older computers use what instead of flash for BIOS
CMOS is a type of memory backed up with a battery sometimes, nowadays we use flash
You can reset flash memory with a jumper that shorts the circuit
(You can remove battery in older computers)
TRUSTED PLATFORM MODULE (TPM)
necessary for full disk encryption
A cryptographic processor generates random numbers and keys.
It also has persistent memory to verify past keys, and also as a digital signature that shows the source of the info
TPMs are protected against brute force attacks
HSM
(Hardware Security Module)
Is used in large environments, and it’s a very high end security device
Uses a plugin card??
IT can backup keys for servers
Lightweight HSMs (smart cards)
You can offload certain cryptographic functions?
How many bits in 32 bit architecture
A 32 bit processor can access up to 2 to the 32nd of information, which is 4gb of values
How many bits can a 64 bit architecture hold?
A 64 bit processor can access 17gb
Can you run 64 bit drivers on an x86 architecture?
No, because a 64 bit OS can run 32 bit apps, but 32 bit OS can’t run 64 bit apps
Can multiple cores have the same cache?
CPUs have mulltiple cores nowadays, and each core can have multiple caches, or there can be a shared cache
Hyper threading technology
Hyper threading technology is a single core that looks like it’s multiple cores, which increases throughput by 15-30%
It’s virtualization software stock in a CPU?
Virtualization software CAN come built into the CPU, Intel Virtualization tech and AMD virtualization can be easier to manage
Sound card
Sound cards are good for high end audio and multiple inputs (headphonejacks, line jacks, digital audio jack)
Integrated graphics card
Many CPUs have an integrated graphics card, sometimes you can have separate GPU
How to connect to graphics card
Integrated graphics card has many types of connectors (VGA, DVI, etc.) and you have to use that connector to utilize that graphics card
Capture cards
Capture cards are good for streaming and external cameras
SDI
(serial digital interface?? Like a HDMI)???
Misc cards
Network Interface Card
Multiport ethernet cards are great for servers
Expansion card best practices
Check the slot type, Hardware and software minimums, utilize Knowledge base and support forums, drivers, etc.
Download Device Drivers from MFR site for latest version
How are adaptor cards cooled?
Some adaptor cards come with their own, other do not
How are small devices cooled?
Small devices have passive cooling
Heat sinks
Heat sinks are usually copper or aluminum alloy and is a good example of passive cooling
Thermal paste vs. thermal pad
Heat sinks require thermal paste or thermal pad (less messy, but less effective and non reusable)
Liquid cooling
Liquid cooling is for higher end systems (gaming, overclocking, etc.)
Liquid systems use a radiator
Computer Power Warning
ALWAYS DISCONNECT POWER WHEN WORKING ON A DEVICE
SOME DEVICES HAVE CAPACITORS THAT WILL STORE ENERGY EVEN WHEN POWERED OFF
Calculate watts
watts=volts x amps
What is Hertz?
Hertz= the amt of cycles per second of electricity
Standard voltage and Hertz
In America: 110-120V, 60 Hz
In Europe: 220-240V, 50 Hz
(Power supply might have a switch to go from 120V to 230V, switch is sometimes automatic
Use a multimeter if unsure.)
Voltages for various cpu components
(DC current is measured in + or -)
PCIe adaptors, fans, hard drive motors,and most modern components use +12V
Legacy motherboards use +5 V
Many components (M.2 Slots, Ram, motherboard logic circuits) are now using +3.3 V
+5SB is for sleep mode
Voltage for integrated LANs
Older components use -12V for integrated LAN or serial ports, PCI cards?
Some provide -5 V for legacy systems
Motherboards connector (power)
24 pin motherboard connector is the main power for motherboard. It provides +3.3V, +/-5V, and +/-12V of power
Redundant Power in servers
Many servers have redundant power supplies.
Ordinarily they’d both take %50 of the load and then when one goes down, you can swap the bad one out while the unit is still running
Fixedvs Modular Connectors
Connectors can be fixed, or modular. Modular allows for only the cords that you need and that will optimize airflow. Some systems allow for hybrid power supplies of both
Is having too much power good or bad?
More power than necessary is a waste. It don’t hurt, it don’t help.
Power supplies are pretty much standardized, but exceptions apply.
What’s the biggest power draw in a system?
Video cards are usually the biggest power draw of a CPU system
Per rating best practices
A good rule of thumb is to take the wattage you calculated, and double it
If you don’t have the exact printer driver can you substitute with something similar?
No. Printer drivers are specific to the device, and you NEED to get this exactly right, also You need to consider the OS and the 32 vs 64 bit drivers
Different printer languages???
PCL (printer command language)was created by HP and is commonly used.
Postscript was developed by Adobe, and is popular with high end printers
Make sure the driver matches the language, because some devices can be configured to work with PCL and Postscript
Printer connection types
Usually connected by the USB connector, also RJ45 is commonly used so ppl can print from anywhere in the network.
You could use Bluetooth also, but the range is limited.
802.11 infrastructure mode (wireless access point) is also common
802.11 ad hoc mode (direct link)
Printer sharing vs. print servers
Printer Share uses one computer as a thouroughfare for all print jobs on the network, but if you turn that computer off, everyone loses access to the printer.
A print server doesn’t require a computer. Jobs are handled directly from the printer via a web-based front end, or an .exe
Different print formats
Duplex: print both sided.
Portrait vs. landscape
Printer authentication
You might want to have user authentication on expensive printers. (password, id badge, etc.)
Audit logs can tell you whos printing what.
Secure prints require you to decide on a pin, then it will hold the job, and not print until you’re physically at the printer to put in the pin
Virtual scanner options
You can scan to email (large scans can fill your mailbox), Scan to a folder using SMB, or send to cloud storage
Laser printer overview
Laser printers use lasers, high voltage, charged ions, heat, and powdered ink to produce very high quality prints quickly. (Requires on-printer memory, often CYMK)
Laser printer processes
- Processing, 2. Charging 3. Exposing (laser) 4. Developing (Toner on drum) 5.Transferring (toner from drum to paper) 6. Fusing 7. Cleaning
Toner with drum replacement
Toner sometimes comes with an Organic Photoconductor Drum (OPC drum), which is sensitive to light and comes in opaque packaging
Power down the printer, then switch them out,
Laser printer page counter
You can check the printer’s page counter which will dictate when certain maintenance tasks have to be performed
Reset the page counter when you’re done.
Printer cleaning
Laser printers have paper and toner dust that has to be cleaned.
Water and isopropyl alcohol on a damp cloth is usually sufficient, but check documentation
Toner needs a specific kind of vacuum, hot water can melt toner, making it harder to clean
Inkjet printer notes
Cheaper, high res, quieter, but ink is expensive
Not archival/ it fadeseventually
It clogs easily, some have a daily clean cycle.
Some cartridges have an integrated printhead, sometimes their separate.
To properly align printer heads, calibrate the printer
MAINTENANCE
Streaks or missing sections of color may be caused by a clogged pinthead
Some printers have a combined cartridge, but you have to replace the whole thing when you run out of one color.
There may be some options to release tension on paper in case of paper jam. Make sure all paper residue is cleaned
On an inkjet printer, streaks or missing sections of color may be caused by…
a clogged pinthead
Thermal printer
If you leave it near heat, the whole page turns black.
NOT for archival information
THere’s a silver heating element.
Make sure you get the exact right kind of paper
On a thermal printer, what can cause missing info on reciept?
A dirty heating element
Thermal printer cleaning tips
ONLY clean where the cleaning element meets paper. They also sell cleaning cards
You can blow them out to get rid of paper debris
Avoid using a vacuum on printers unless it’s specifically designed.
Avoid storing thermal paper anywhere near heat
Impact printer notrf
Presses against the paper to leave indented dots.
Cheap and good for multiple copies, but it’s noisy and has bad graphics
Why is the printers larger on impact printers?
THe printhead is larger because it contains a heat sink.
The ink is contained on a printing ribbon which is made of fabric and is of a proprietary size
What color is associated with mainframe
GREEN BAR PAPER IS ASSOCIATED WITH MAINFRAME PRINTERS??
Impact printer maintenance
Print ribbon goes bad and ink gets lighter and lighter
The printhead can get messed up as well. When you change the printhead, change the ribbon too
When replacing the paper, you must line it up perfectly
FDM
FDM Fused Deposition Modelling (Filament) melts filament to create 3D objects. It’s a good all around printer.
A stereolithography (SLA) printer uses resin and makes very clean, finely detailed 3D prints.
THe entire print hangs from a build platform and is dipped bit by bit into the resin.
A stereolithography (SLA) printer uses resin and makes very clean, finely detailed 3D prints.
THe entire print hangs from a build platform and is dipped bit by bit into the resin.
What are some examples of public servers?
Amazon, microsoft, rackspace, etc.
Internal cloud characteristics
Internal cloud has no shared resources.
You need to have your own data center, you gotta handle up front cost, but there’s no ongoing subscription cost.
External clouds characteristics
underlying ifrastructure is owned by a third party, cost may be up front or metered.
Metered costs are usually low up front, and you pay for uploads,downloads, storage, etc.
Non metered is charged monthly.
Rapid Elasticity and File synchronization
Virtual machine notes
Been around since 1967 IBM mainframes
You can run legacy software on a vm
Hypervisor, or Virtual Machine Manager manages the guest OS
Certain CPUs are designed for virtualization
Can virtual machine replace another security measure?
NO. EVEN WITH A VM, YOU STILL NEED TRADITIONAL SECURITY CONTROLS: host based firewalls, anti-virus, anti-spyware
Bridged Network Address-
Bridged Network Address- Every VM has its own IP address. YOu don’t have to worry about network address translation.
Private Address- (VM)
You lock down the VM so there’s no communication outside of the virtualized environment
Change control
a formal process for managing change.
It helps avoid downtime, mistakes, and confusion, and is corporate policy
(Estimate risks, formulate recovery plan, establish tests, document/get approval for change)
TROUBLESHOOTING PROCESS
Somethings Broken-Identify the Problem
Establish some theories- test the theories- evaluate if it’s working- repeat
Create a plan of action-implement plan- verify full system functionality- document findings
IDENTIFY THE PROBLEM
Gather info (duplicate the issue, if possible, get a screenshot)
Gather symptoms (may be multiple symptoms)
Question user (email and phone calls)
Determine if anything has changed
Approach multiple problems individually
Get backups of everything, take notes
ESTABLISH A THEORY
Occam’s Razor: the simplest explanation is often the most likely
Consider everything (think outside the box)
Make a list of all possible causes
Get documentation, maybe someone else already dealt with this exact problem
TEST THE THEORY
Go through theories, easiest, to hardest
CREATE A PLAN OF ACTION
Correct the issue with minimum impact, always include a rollback plan
Have a plan B and a plan C
IMPLEMENT THE SOLUTION
Fix the issue (usually there’s time constraints)
Escalate as necessary (call in help)
VERIFY FULL SYSTEM FUNCTIONALITY
The test should be a part of the plan
Implement preventative measures
DOCUMENT FINDINGS
List symptoms, changes, and results
Most databases will have help desk software or knowledge-base software that heps prevent
POST (diagnostic)
POST (Power On Self Test) designed to make sure that all of the main components are available. (CPU, VIDEO, KEYBOARD, MEMORY, etc.)
Beep codes:
You get a beeping sound and a visual message, the beeps are there if your computer screen doesn’t work
Beep codes differ from one brand to the next, so check motherboard documentation
Beep codes might tell you that you have a bad video, bad memory, or bad cpu/no cpu
What to do if date and time are off in the BIOS
Date and time setting might be off in the BIOS. change the battery
What is a good first step of a computer crashes
You can go to the !!!WINDOWS EVENT VIEWER!!! To see what the event logs say about the problem. It may not help much.
Contact MFR of computer and of the software that is causing the error. They can access DEBUG LOGS???
Blue Screen
can be caused by bad hardware, bad drivers, or a bad application
You can get a previous configuration: Last Known Good, System Restore, or Rollback Driver!!
Sometimes you can boot up in SAFE MODE!!! (certain drivers aren’t loaded in safe mode, so it can help pinpoint the problem)
Remove and reseat new hardware.
SPINNING BALL OF DEATH (MacOS)
If it doesn’t go away, you gotta power down and power back up.
Possible reasons:Application Bug, Bad hardware/memory, or Slow paging to disc.
If you gotta restart, go to console logs
BLACK SCREEN
Start with the cabling for power and connection
Check input settings HDMI, DVI, etc.
Check brightness settings,
swap with a known good monitor.
If The screen works until WIndows loads, then you want to startup in WINDOWS VGA MODE. (vga mode is a generic mode that works with almost every monitor)
NO POWER:
Check power supply with multimeter
Check fans, if fans are on, trace the power to see where the power is coming from.
Check POST
SMOKE AND BURNING SMELL
If you see/smell smoke, power down
Locate bad components on motherboard
INTERMITTENT SHUTDOWN
In windows, restart and check event viewer.
Might be heat related, might be faile hardware (check device manager)
Detailed diagnostics (Proccess of elimination, see what’s working well.)
APPLICATION CRASHES
It may provide an error msg, might just disappear, but it won’t offer much info
Check event viewer for more info.
Reliability monitor will provide a graphical representation
If you think you know which app is bugging, Uninstall and reinstall latest version
GRINDING NOISES
Computers should hum, not grind
It’s probably the HDD or the fan
Rattling might be from loose components
Scraping noise might be from HDD, very serious
Clicking is usually the fan
What causes a popping sound in a computer
A pop is usually the capacitor on a motherboard (bulging cylinders, very faint)
LOCKUPS
System Completely Stops, usually not much in the event logs
Check for anything that is still responsive, e.g hard drive, status lights, num lock button, try ctr-alt-del
See if any new work has been done recently (hardware drivers, software patches)
Low resources (ram and storage)
Hardware diagnostics might be necessary
CONTINOUS REBOOTS
How far does the boot go before it restarts (does it stop at the BIOS, at the OS logo?)
If you have a bad driver, hit F8 and boot from last known working configuration
Hit F8, safe mode, disable automatic restarts in system properties (gives you time to read blue screens or error msgs)
Try to swap harware (adapter card, memory, etc.)
INCORRECT DATE AND TIME
Gotta change battery, or else you’ll get an error msg.
Changing battery will NOT alter BIOS, which is stored on motherboard in flash memory. (jumper wire)
SLUGGISH PERFORMANCE
Task manager, view CPU utilization per process
Check performance tab as well
If low utilization, it may be a problem with the I/O devices
Windows updates might slow down computer without giving info on background processes
Check Disk Space
Sluggish performance pt 2
Power throttling in certain modes, (power saving mode)
Hot computers might slow down to stay cool
Antivirus might be working in the background as well
Fans and Heat sinks have to be clear and clean.
Temperature monitoring software is built into the BIOS, but you can get a 3rd party monitor like HWMONITOR for more info
SMOKE AND BURNING SMELL
If you see/smell smoke, power down
Locate bad components on motherboard.
INTERMITTENT SHUTDOWN
In windows, restart and check event viewer.
Might be heat related, might be faile hardware (check device manager)
Detailed diagnostics (Proccess of elimination, see what’s working well.)
APPLICATION CRASHES
It may provide an error msg, might just disappear, but it won’t offer much info
Check event viewer for more info.
Reliability monitor will provide a graphical representation
If you think you know which app is bugging, Uninstall and reinstall latest version
GRINDING NOISES
Computers should hum, not grind
It’s probably the HDD or the fan
Rattling might be from loose components
Scraping noise might be from HDD, very serious
Clicking is usually the fan
A pop is usually the capacitor on a motherboard (bulging cylinders, very faint)
LOCKUPS
System Completely Stops, usually not much in the event logs
Check for anything that is still responsive, e.g hard drive, status lights, num lock button, try ctr-alt-del
See if any new work has been done recently (hardware drivers, software patches)
Low resources (ram and storage)
Hardware diagnostics might be necessary
CONTINOUS REBOOTS
How far does the boot go before it restarts (does it stop at the BIOS, at the OS logo?)
If you have a bad driver, hit F8 and boot from last known working configuration
Hit F8, safe mode, disable automatic restarts in system properties (gives you time to read blue screens or error msgs)
Try to swap harware (adapter card, memory, etc.)
INCORRECT DATE AND TIME
Gotta change battery, or else you’ll get an error msg.
Changing battery will NOT alter BIOS, which is stored on motherboard in flash memory. (jumper wire)
‘Cannot read from the source disk’
Could be from slow performance (constant LED activity on Hard drive light, or constantly retrying)
Loud clicking, grinding, or scraping
BOOT FAILURE
‘Drive not recognized, boot device not found.’
‘OS not found’ (can reach the hard drive but can’t reach the OS)
Check your cables
Check boot sequence in BIOS (check for removable disks, especially USB, and check for disabled storage interfaces)
Boot failure If booting from a new installation/hardware config:
Check data and power cables, check sata interfaces,
Try the drive in a different computer
DATA LOSS/CORRUPTION
Recovery is expensive and not always successful
SSDs may allow to read, but not to write (data can be permanently lost)
RAID NOT FOUND
(dell config utility?)
If a Single drive has failed, you could usually use a RAID manager in the system to get more info
S.M.A.R.T- Self Monitoring Analysis and Reporting Tech
???
EXTENDED READ/WRITE TIMES
A lot happens when reading/writing data. Memory access, communication across the bus, spinning drive access reading data to different storage devices
There can be delays anywhere within this process.
Measure the IOPS (Input/Output Operations Per Second) to get big picture view of data used.
200 IOPS for HDD, 1,000,000 IOPS for SSD
MISSING DRIVES IN OS
Check the BIOS, Check for bad drives/cables, reseat the drives
If it’s a external drive, make sure you got power to the drive
If the missing drive is a NETWORK SHARE??
you may have missed that drive being mounted during the startup process, try to reconnect, or run LOGIN SCRIPT?? Again
Video troubleshooting first steps
Check connection, Check input selectionTry a known good monitor,check brightness ctrls, load in f8 (VGA mode/safe mode?)
IMG quality problems
Check the cable pins, ESPECIALLY when missing a color
Distorted geometry
CHange OS refresh rates and resolution settings
Disable hardware acceleration
NATIVE RESOLUTION
LCD has a fixed number of pixels
Video looks best when the video matches the display’s native resolution
Try to use a multiple of native resolution and maintain proportions
BURN-IN
Is a problem across the board
Some displays will pixel shift to prevent burn-in
On LCDs it’s called image sticking, you want to show a white screen for a while to reset
POOR BATTERY HEALTH
Phone batteries will degrade over time.
Searching for signal will worsen the battery life, so go in airplane mode when you’re out of network
Check the battery features to find our what’s consuming the battery life
SWOLLEN BATERY
Significant fire risk
Have to dispose properly and replace with a known good battery
BROKEN SCREEN
Perfect time for a backup,
Sometimes you have to replace entire display
Maybe tape it down to prevent cuts
IMPROPER CHARGING
Clean out with safety pin
Check cable
Check outlet with multimeter
POOR OR NO CONNECTIVITY
Wifi has a limited range, interference can limit throughput, May need to change channel/frequency configuration
LIQUID DAMAGE
Phone manufacturers use liquid contact indicator to know if there was a spill
Power down, break it down,put it in silica gel
Leave it ALONE for at least a day
OVERHEATING
Phone will automatically shutdown
Charging,using, display, and CPU all make heat internally
DIGITIZER ISSUES
Touchscreen can be completely black, or unresponsive
Hold the power buton for a soft reset, if you can’t access the screen, hard reset by holding the power and volume/home buttons for 10 seconds
PHYSICALLY DAMAGED PORTS
Charging ports are built into the system board, so to fix it, you have to swap the entire board
MALWARE
Look for unusual apps, large data transfers, pop up messages, high CPU usage, excessive battery use, battery overheating
Try a security app or virus scanner
CURSOR DRIFT
Common on older machines
Use a touch calibration app
TESTING THE PRINTER
Print test is built into windows
THere can be diagnostics built into the printer itself as well
BAD OUTPUT
Lines down the page: inkjet, check the inkjet, laser, check the drum
Faded print check the toner/ink
Echo images, laser printer optical drum isn’t being cleaned properly
GARBLED PRINT
Wrong driver, or wrong printer language
Print a test page to verify functionality
Toner not sticking to the paper
Touching the page smudges it (fuser assembly not working)
Creased paper in printer
If the paper is coming out creased, might be a blockage, or maybe worng weight of paper
Corrupted print job
If you get a corrupted printjob then the print spooler will crash and backup the print queue, delete the corrupted file and you should be good
Color accuracy for printers
COLOR ACCURACY
Calibrate screen (3rd party options)
Then calibrate the printer
GRINDING NOISES in printer
Never a good sound
Could be a paper jam, could be mechanical and require professional help.
Printer finishing options
Some printers have staplers built in, Some printers can bind like a book, some printers can punch holes
INCORECT PAGE ORIENTATION
Check settings
Check the default printer settings
5.7 TROUBLESHOOTING NETWORKS
Check for a link light
Now, see how far you are into the network
Ping the loopback address, if it responds, then look further
Ping local IP address assigned by network adapter
Next, ping the default gateway (critical link between your device and the rest of the world)
Finally, Ping external websites, like google
INTERMITTENT WIRELESS CONNECTIVITY
Could be Interference, check signal strength
Check transmitting and receiving antennae
Channels are usually automatical, but look for manual tuning
Bounce and latency
You may have to move closer to the access point
PREDICTABLE FORMS OF INTEREFERENCE
Flourescent lights, microwave ovens, cordeless phones, high power sources
UNPREDICATBLE INTERFERENCE is other tenants
Check the signal to noise ratio SNR (WIndows performance monitor)
LIMITED OR NO CONNECTIVITY
Check IP address (ideally assigned by a DHCP server)
If you see an Automatic Private IP Address APIPA then you can’t get one from DHCP
Check local gateway and remote ip address???
JITTER
There’s no retransmission on live streams
Jitter is a statistical measure of the time between frames
Voice calls become choppy when there’s a lot of jitter
POOR VOIP QUALITY
You neeed high speed low latency internet
Check local network equipment, some old routers can’t handle the throughput
PERFORM A PACKET CAPTURE TO VIEW NETWORK PERFORMANCE??
LATENCY
Some latency is normal
You gotta examine latency at every sep along the way, which will require MULTIPLE MEASUREMENT TOOLS??
Packet captures are a great help. You can et details down to the microsecond
PORT FLAPPING
Link light goes on and off
Try using a cable tester
Move to a different interface and see if that helps
The problem may also be with the comuter or NIC for the device
DEAD PIXELS
if the pixels are always dead, it’s a manufacturer defect
Clean the monitor
You gotta replace the monitor
FLASHING IMAGE
check the cable, reseat it, replace it if that don’t work
Check the monitor settings first
INCORRECT COLOR DISPLAY
Monitor settings (tint, color presets, factory reset)
Driver config
OS config (some have a night light settings)
LCD projectors
Metal halide lamp gets hot, lamps are expensive, so leave thze fan on after use
Intermittent shutdown-cooling problem
Some projectors have airflow filters that need to be replaced
LOOPBACK:
127.0.0.1 (127.x.x.x) Simply refers to your own system
CMD ping 127.0.0.1 (should get a reply when things are working well)
Verifies that the NIC is working.
