Chapter 2: Storage Devices and Power Supplies Flashcards
Define HDD
Hard disk drive / hard drive / hard disks. Used for permanent storage and quick access
3 Critical components of a HDD
Controller, Hard Disk, HBA
What is a HDD’s Controller?
The controller chip controls how the drive operates and how the data is encoded onto the platters. It controls how the data sends signals to the various motors in the drive and receives signals from the sensors inside the drive. Most common: PATA (IDE), SATA
What is the HDD’s hard disk?
This is the physical storage medium. Stacked platters.
What is a HDD’s HBA?
Host bus adapter. Translator, converting signals from the controller to signals the computer can understand. HBA is usually located on the motherboard.
Identify the sector and track colored in this image.
Red: Track; Blue: Sector
Define a Sector
magnetic domains that represent the smallest units of storage on the discs’ platters. Magnetic-drive sectors commonly store only 512 bytes (1⁄2KB) of data each
CHS
cylinders/heads/sectors
The components of the basic geometry of a HDD
The basic hard disk geometry consists of three components: the number of sectors that each track contains, the number of read/write heads in the disk assembly, and the number of cylinders in the assembly.
How do you determine the number of cylinders on a hard drive?
The number of cylinders is the number of tracks that can be found on any single surface of any single platter.
It is called a cylinder because the collection of all same-number tracks on all writable surfaces of the hard disk assembly looks like a geometric cylinder when connected together vertically.
A cylinder on a HDD assembly with 3 platters is comprised of how many tracks?
6
one track on each side of a platter.
How many heads are contained in a HDD assembly?
One for each writable surface, so two per platter.
What does a CHS geometry of 16383/16/63 mean?
16,383 cylinders
16 heads
63 sectors per cylinder
What is the capacity of a HDD with a CHS geometry of 16383/16/63?
7.87GB
KB=(CHS)/2
GB=KB/1048576
Multiply 16,383 cylinders by 16 heads to get the total number of tracks, 262,128
Multiply 262,128 tracks by the number of sectors per track, 63, to get thee total number of sectors, 16,514,064
Each sector is 1/2 a KB. Get the number of KB by dividing 16,514,064 by 2.
Capacity = 8,257,032KB
Get the number of MB by dividing that figure by 1024
Capacity = 8063.5078MB
Get the number of GB by dividing that figure by 1024
Capacity = 7.87GB
Define SSD
Solid State Drives
solid-state drives (SSDs) have no moving parts but use the same solid-state memory technology found in the other forms of flash memory. All solid-state memory is limited to a finite number of write (including erase) operations.
Wear Leveling
The process of spreading read/write operations evenly over an entire SSD, so that the finite number of read/writes is spread throughout the disk
Benefits of SSD over conventional HDD
Read contents more quickly
Consume less power
Produce less heat
Are more reliable and less susceptible to damage from physical shock and heat production
Disadvantages of SSD over conventional HDD
More expensive per byte
Limited write operations
Examples of Optical Disk Drives
Blueray
DVD (Digital Video Disc)
CD (Compact Disc)
Define CD-ROM
Compact Disc Read Only Memory
650, 700, 800, or 900MB capacities
Read only
What speed is 1X for a CD-ROM?
150KBps
How did manufacturers increase the speed CDs could be read from 1X to 8X
They spun the disk faster.
At 8X the CD was spinning so fast that increasing speeds risked breaking the disk apart.
Subsequent speed increases were achieved through other technological advancements
What is the standard DVD-ROM transfer rate for 1X?
1.4MBps
What is the difference between these two CD-ROM devices?
that CD-R drives can write to a
CD-R disc only once. A CD-RW drive can erase information from a CD-RW disc and
rewrite to it multiple times.
What does this rating mean for a CD-RW drive?
52X-32X-52X
it writes at 52X, rewrites at
32X, and reads at 52X
What does it mean when a DVD is described as this:
DVD-ROM
Purchased with data encoded; not able to be changed
What does it mean when a DVD is described as this:
DVD-R, DVD+R
Purchased blank; able to be written to once and then treated like a
DVD-ROM
What does it mean when a DVD is described as this:
DVD-RW, DVD+RW
Purchased blank; able to be written to and erased multiple times;
session usually must be closed for subsequent access to stored data
What does it mean when a DVD is described as this:
DVD-RAM
Purchased blank; able to be written to and erased just like a hard
or floppy disk; no session to close before subsequent access to
stored data
BD-R versus BD-RE
BD-R Blueray Disk that’s recordable once (Like CD-R)
BD-RE: Blueray Disk that’s re-recordable (Like CD-RW)
What does DMA or PIO allow?
DMA or programmed
input/output (PIO)
methods for improving drive
performance by allowing the drive to write directly to RAM, bypassing the CPU when
possible.
IDE is also known as
PATA
What does SATA stand for
Serial Advanced Technology Attachment
What type of connection is this?
SATA
Define SCSI
Small Computer System Interface
Internernal or External storage device.
What is this cable?
External SCSI cable.
Describe this configuration.
Internal SCSI cable connects two devices to the motherboard.
Both ends are terminated (one to a CD-ROM, the other to the motherboard).
The middle device (the HD) is daisy-chained connected.
Each SCSI device must have _____, set by ____.
Each device must also have a unique SCSI ID number. This number can be assigned by the jumper (with internal devices) or with a rotary switch (on external devices).
Define RAID
Redundant Array of Independent Disks.
way of combining the
storage power of more than one hard disk for a special purpose, such as increased performance
or fault tolerance.
Two ways to implement RAID and the most efficient method.
Software or Hardware implementations.
Hardware implementation is more efficient and performs better.
RAID 0 is also known as
Disk Stripping
RAID 0
Data is written across multiple drives, so one drive can be reading or writing while the
next drive’s read-write head is moving. This makes for faster data access. However, if any one
of the drives fails, all content is lost. Some form of redundancy or fault tolerance should be
used in concert with RAID 0.
RAID 1
disk mirroring
writing all data simultaneously to two separate drives. If one drive fails, the other contains
all the data and will become the primary drive
Only two drives can be used in a RAID 1 array
RAID 5
Combines the benefits of both RAID 0 and RAID 1
Each stripe places data on n–1 disks, and parity computed from the data is placed on the
remaining disk. The parity is interleaved across all the drives in the array so that neighboring
stripes have parity on different disks. If one drive fails, the parity information for the
stripes that lost data can be used with the remaining data from the working drives to derive
what was on the failed drive and rebuild the set once the drive is replaced
Minimum number of drives for RAID 5
A minimum of three drives
is required for RAID 5
What is the capacity of quarter-inch cartridge tape backups?
200KB - 525MB
What is the capacity of digital linear tape (DLT)?
Up to 160GB
What is the capacity of 8 millimeter backup tape?
800 GB
What is the capacity of linear tape-open backup tapes?
1.5TB
Examples of flash memory
SD cards
USB flash drives
Other solid state drive solutions
What does it mean for a device to be hot swappable
You can insert and remove the device with the system powered on.
A non-hot-swappable device can’t be inserted or removed whiel the power is on.
A non-hot-swappable device may also be known as
Cold Swappable
Within hot-swappable devices, there is a category of ‘warm-swappable’ devices. What makes these devices different from hot-swappable devices?
While you can add or remove a warm-swappable device while the PC’s power is on, you should use a software utility to disconnect the device first.
Best example: Flash USB memory stick, which should be removed via the “Safely Remove Hardware” application. If you don’t use that utility, data loss could occur.
Power Supply
The device in the computer that provies power to all PC’s components.
A power supply converts ______ to D/C voltages
110Volts or 220Volts A/C
Examples of DC voltage levels that PC components require to operate
+3.3VDC
+5VDC
-5VDC (older systems)
+12VDC
-12VDC
Note: VDC here means volts of direct current
Watt
A unit of power
Most computers require power supplies within what watt range?
250 - 500 watts are required for most computers.
In a power supply, what is the purpose of the red, recessed switch in the back?
The switch allows for you to switch between two different voltage levels for different countries. Popular choices include:
110 and 220 volts
115 and 230 volts
120 and 240 volts
If the incorrect voltage is selected via the red, recessed switch behind the power supply, what could happen?
If you’re in the US and select the higher voltage, the power supply won’t receive as much power as it expects and the system will not boot.
In Europe & elsewhere, power lines provide more voltage. Selecting the lower voltage would result in the power supply receiving more power than it expects, and the PC could catch on fire.
What’s the best way to handle a malfunctioning power supply?
Get rid of it. Attempting to fix a power supply is asking for your house to get burned down.
Common “Classic” power connectors include what
AT system connectors
Standard Peripheral Power Connector
Floppy Drive Power Connectors
Name this type of power connector
AT Power Connector
What does the AT System connector power?
Older, AT-style motherboards.
Only legacy computers with AT and baby AT motherboards used this type of power connector.
Name this type of power connector
Standard peripheral power connector
Standard peripheral power connectors are also known as
Molex connectors
Name this type of power connector
Floppy Drive Power Connector
Floppy drive connectors are also known as
Berg connectors
What does a laptop use for its power supply?
An AC adapter, which does esentially the same thing as a traditional power supply.
