Memory and Storage (Chapter 3) Flashcards
System memory
The memory that the system uses to execute calculations
Data Bus
Computational information that will be read/written on RAM by the CPU travels via this bus
- The width of the pathway determines the amount of data transferable per clock cycle
- 64 bits wide
Address Bus
The bus in which memory address is transferred
- Width of address bus determines the amount of memory locations the CPU can keep track of
- x32 bit system with 32-bit address bus can access 4GB of memory
- x64 bit system with 48-bit address bus can access 256TB of memory
RAM Types
DRAM - Dynamic Random Access Memory
- needs constant refreshing
SDRAM - Synchronous Dynamic RAM
- Synchronized to system clock
DDR SDRAM - Double Data Rate SDRAM
- Synchronized to double the system clock rate
DDR3
Data transfer (MT/s) = 800 - 2133
Transfer Rate (Gbps) = 3 - 8
- up to 16BG per DIMM
- 240 pins
- 1.5 - 1.35v
DDR4
Data Rate (MT/s) = 1600 - 2133
Transfer Rate (Gbps) = 12 - 25
- up to 64GB per DIMM
- 288 pin
- 1.2v
DDR5
Data transfer (MT/s) = 4800 - 6400
Transfer Rate (Gbps) - 64 -128
- up to 128GB per DIMM
- 288 pins
- 1.1V
DIMM
Dual Inline Memory Module
SO-DIMM
Small Outline Dual Inline Memory Module
- 32 or 64 bit pathways
- used for laptops
DDR3 & 3L
- 204pin
-3L = low voltage SO-DIMM
DDR4
- 260pine
DDR5
-262pin
Parity & ECC RAM
Parity RAM
- An error checking method where each byte of memory is accompanied by a ninth bit that is used to check if the data is corrupted
ECC Error Correcting Code
- detects and corrects errors on the fly
Hard Disk Drives (HDD)
A devices that provides non-volatile mass storage space via magnetic disks.
- Data is written on concentric rings called tracks
- the tracks are then further divided into sectors. Up to 4096-Byte sectors
- up to 8 TB storage
3.5” used in desktops
2.5” used in laptops
Access Time
Speed at which memory can be addressed and utilized
Internal Transfer Rate
The read/write operation speed at which the drive is capable of
External Transfer Rate
Speed at which data can be transferred to the CPU across the bus
Early-Life Failure Rate
Rate at which a device could fail
Mean time Between Failures (MTBF)
rating on a devices that predicts the time between failures
Life Expectancy
The length of time a device is expected to be operational for
S.M.A.R.T.
A standardised Technology across all storage drives designed to alert users of potential disk failure
Host Bus Adapter (HBA)
A component that allows a storage device to exchange data with a computer via a particular interface such as SATA, NVMe
Drive Controller
Circuitry in the hard disk that allows the transfer of data from the disk to the CPU/RAM via the HBA
SATA
Serial Advanced Technology Attachment
Storage interface that connects the storage drive to the motherboard
7 pin data cable
15 pin power cable
Solid State Drives (SSD)
A non-volatile storage devices that has no moving parts but uses chips to store data
- Quieter and more power efficient
Non-Volatile Memory Express (NVMe)
A protocol created for connecting flash memory devices directly t the PCIe bus
-up to 32Gbps
RAID
Redundant Array of Independent Disks
- An array of multiple disks that act as fault tolerance and/or increases disk space and speed
RAID 0
Disk Stripping
an array of disk where parts of the data is written across multiple drives to improve performance by allowing the system to read/write data across all drives at the same time
- requires 2 or more drives
- No fault tolerance
- Storage space is the total sum of all drive storage space capacity
RAID 1
Disk Mirroring
An array of disks where each main disk has a back up copy
- Fault tolerance
- Requires multiples of 2 disks
- Storage space of half the sum total of all drives disk space capacity
RAID 5
Disk Stripping with Parity
An array of disks that stores parts of data across all drives with a parity of a portions drive on another drive
- requires 3 drives
- Fault tolerance
- 2/3 of the sum total of all disk space is accessible
RAID 10
Nested RAID configuration consisting of RAID 0 and RAID 1, where each disk stripping has a mirror disk
- Fault tolerance
- requires at least 4 disk
- half of the sum total of drive disk space is accessible
Master Boot Record (MBR)
A portion on a disk that stores the disks partitions configuration
Global unique ID Partition Table (GPT)
Modern partition system that allows large numbers of partitions with large partition sizes
Boot Repair Tools
Windows system commands using command prompt that attempts to fix system boot issues
bootrec /fixmbr
-attempts to repair MBR
bootrec /fixboot
-attempts to repair boot sector
bootrec /rebuildbcd
- add missing windows installations to boot configuration database (BCD)
Dual channel
All RAM types and motherboard can support dual channel
Triple Channel
Only DDR3 and DDR3 compatible motherboard can support triple channel
Quad Channel
DDR3, DDR4 & DDR5 memory can support quad channel
SATA Speed
SATA 1 = 1.5Gbps
SATA 2 = 3Gbps
SATA 3 = 6Gbps
AHCI
Advanced Host Control Interface
- a logical interface (language) designed for SATA drives to be able to communicate with the motherboard
- SATA 3: 6GB
M.2
SSD form factor that connects the storage drive directly into the motherboard.
- not hot-swappable
Wear Leveling
A technology for SSD that stores data on different parts of the NAND chips to prevent any single memory location from being over used.
Hybrid Drive
SSHD
- a drive that contains a solid state drive portion that acts as a large cache that stores frequently used data, and a magnetic drive portion which is used to store less frequent data
Hardware RAID Config
A method of setting up RAID via an adapter card or via the motherboard UFFI/BIOS setup
Software RAID config
Windows provides option to setup RAID, uses standard disk and controllers.
Only supported on Windows Professional/Enterprise
Command to fix MBR
Bootrec /fixmbr
Command to fix boot sector
Bootrec /fixboot
Command to fix missing windows installation
Bootrec /rebuildbcd
PSU
A power supply unit that transforms AC current into DC current into 3.3v, 5v and 12v for different components on the motherboard
