Section 3.2-3.4: Memory, Storage, and Motherboards

- Random Access Memory
- most common, but not the only kind
- data and programs can only be used when moved to RAM, not storage

- Dual Inline Memory Module, electrical contacts are different on each side
- 64 bit data width

- Small Outline Dual In-line Memory Module
- half the width as a DIMM
- used in laptops and mobile devices

- needs constant refreshing, without refreshing - the data in memory disappears
- random access, any storage location can be accessed directly
- unlike magnetic tape

- synchronus DRAM with the common system clock
- queue up one process while waiting for another
- classic DRAM didn't wait for a clock signal

- double data rate 3 SDRAM
- twice the data rate of DDR2
- larger chip capacities, maximum 16GB per DIMM
- no backwards compatibility

- speed increases over DDR3
- faster frequencies, maximum 64GB per DIMM
- also no backwards compatibility

- faster data transfers between the memory module and motherboard
- maximum 64GB per DIMM
- key has moved, no backwards compatibility

- virtual RAM, swap file
- swaps currently unused application data to storage, frees up space for other applications
- managed automatically by the operating system, some configuration settings are available

- dual-channel, triple-channel, or quad-channel
- memory combinations should match

- adds additional parity bit
- won't always detect an error, can't correct an error
- even parity - parity bit makes an even number(of ones)

- error correcting code
- detects error and corrects on the fly
- not all systems use, looks the same as non-ECC memory

- hard disk drives, non-volatile magnetic storage
- rapidly rotating platters
- random-access, retrieve data at any time
- physical mechanical failure possibility
- 3.5''

- solid-state drives, non-volatile memory
- very fast performance, no spinning delays
- 2.5''
- S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) data provides performance metrics

- Mini-SATA
- shrink the SATA drive into smaller devices
- smaller than 2.5'' SATA drives
- used shortly, quickly replaced by m.2

- SATA was designed for hard drives and uses Advanced Host Controller Interface to move drive data to RAM
- SATA revision 3 throughput up to 600MBs
- SSDs need a faster communication method
- Non-volatile Memory Express designed for SSD speeds, lower latency and supports higher throughputs

- smaller form factor, no SATA data or power cables
- can use a PCI express bus connection, 4GBs throughput
- faster when using NVMe PCIe x4
- needs to be compatible with slot key
- supports B key, M key, or B and M key

- M.2 doesn't guarantee NVMe
- may be using AHCI
- motherboard may only support one type of key

- flash memory, EEPROM(Electrically erasable programmable read-only memory)
- non-volatile memory, no power required to retain data
- limited number of writes, can still read the data
- easy to lose/damage, not designed for archival storage

- small bumps read with a laser beam, microscopic binary storage
- archival media, relatively slow
- many different forms ex: CD-ROM, DVD-ROM, blu-ray
- internal and external drives for application installations

- Redundant Array of Independent Disks, inexpensive disks
- not backup
- different RAID levels, some are redundant, some are not

- striping
- file blocks are split between two or more physical drives
- high performance, data written quickly
- no redundancy, drive failure breaks the array

- mirroring
- file blocks are duplicated between two or more physical drives
- high disk utilization, required disk space is doubled
- high redundancy, drive failure does not affect data availability

- striping with parity
- file blocks are striped along with a parity block and requires at least three disks
- efficient, files aren't duplicated, but space is still used for parity
- high redundancy, data is available after drive failure
- parity calculation may affect performance

- (1+0) stripe of mirrors
- speed of striping, redundancy of mirroring
- need at least 4 drives

- Advanced Technology Extended, made by Intel in 1995
- 20 pin connector, 24 pin connector additional 4/8 pin connector

- VIA technologies in 2001
- lower power, small form
- mini-ITX is screw-compatible with ATX
- single-purpose computing like streaming media

series of communication paths

- Peripheral Component Interconnect, 1994
- 32-bit and 64-bit bus width
- parallel communication

- PCIe, replaces older PCI
- serial connection, unidirectional serial lanes
- full-duplex lanes

- main motherboard power, provides +3.3V, +/-5V, and +/- 12V
- added for PCI express power
- 20 pin was original ATX standard
- can connect a 24-pin connector to a 20-pin motherboard
- some cables are 20-pin + 4-pin

- +12V power
- additional 12V power for older motherboards
- primarily for CPU

- pin headers
- simple electrical interface, connector is attached to the header
- used for power, lights, buttons, peripheral connections

- Intel and AMD
- different sockets, motherboard is designed for only one
- historically Intel is for performance and AMD is for value as it is less expensive

- multisocket, supports multiple physical CPU packages, splits the load
- memory slots, supports 4+ modules, expansion slots
- designed for a rack-mounted system, larger ATX-sized system

- full-size or compact or monitor-only systems
- single cpu, usually two or four memory slots
- may have limited options for expansion slots

- laptops, small and light
- CPUs, limited in speed, thermal throttling
- limited system modification for memory/CPU/functionality
- for portability, smaller devices, low power consumption

- proprietary, built to fit
- difficult replacement, swap entire board

- Basic Input/Output System
- software used to start your computer, the firmware
- system BIOS, ROM BIOS, ROM or flash memory
- initializes CPU and memory, builds the workspace
- POST(Power-On Self-Test)
- looks for a boot loader to start the operating system

- original BIOS, 25+ years old
- older operating systems talked to hardware through BIOS instead of accessing hardware directly
- limited hardware support, no drivers for modern network, video, and storage devices

- Unified Extensible Firmware Interface, based on Intel's EFI
- defined standard implemented by manufacturers
- designed to replace legacy BIOS

setup button: Del, F1, F2, Ctrl-S, Ctrl-Alt-S

- Windows 8/10/11 - no option to press a button to start bios
- windows starts immediately
- shut down doesn't actually shut down all the way, this enables a fast startup
- hold shift when clicking restart
- interrupt normal boot three times

USB drive >> SSD >> HD

- security challenge, small storage devices and large capacities
- connections are convenient and high speed
- US Department of Defense banned USB flash media for 15 months in 2008 because of SillyFDC worm

- cpu fans, chassis fans
- motherboards include an integrated fan controller and temperature sensors
- motherboard increases/decreases fan speeds

- malicious software can own your system with malicious drivers or OS software
- part of the UEFI specification
- uses digital signatures to run software, cryptographically secure
- supported in windows and linux

- BIOS includes manufacturer's public key
- signature is checked during BIOS update
- BIOS prevents unauthorized writes to the flash
- verifies that bootloader is signed with a trusted certificate

- needs password to start the operating system
- supervisor password will restrict BIOS changes, and is needed to change any BIOS configurations

- CMOS(complementary metal-oxide semiconductor), type of memory, backed up with a battery
- usually flash memory, easily stored and accessed
- can reset with a jumper, short(connect) two pins on the motherboard

- not usually needed today
- bad battery will require a BIOS configuration or date/time configuration on every boot
- on older systems, removing the battery resets the BIOS configuration
- newer computers use a jumper

- Trusted Platform Module, specification for cryptographic functions
- cryptographic processor enables random number generator and key generators
- persistent memory, comes with unique keys burned in during production
- versatile memory, storage keys and hardware configuration information
- password protected, no dictionary attacks

- Hardware Security Module, used in large environments
- adapter plug-in card or separate hardware device you install in a server
- key backup, secured storage for servers
- lightweight HSMs ex: smart card, USB, flash memory
- cryptographic accelerators built into the hardware to offload CPU overload from other devices

- 32-bit vs 64-bit, processor specific
- 32-bit processors can store 2^32 values
- 64-bit processors can store 2^64 values
- 4GB vs 17 billion GB, the OS has a maximum supported value

- hardware drivers must match OS version
- 32-bit(x86), 64-bit(x64)
- 64-bit OS can run 32-bit apps, but not vice versa
- 32-bit apps: \Program Files (x86)
- 64-bit apps: \Program Files

- Advanced RISC Machine, CPU architecture developed by Arm Ltd
- simplified instruction set, efficient and fast, less power/heat

- dual core/quad-core/octa-core/multi-core
- multiple cores means each core has its own cache
- the entire chip may have a shared cache

- HTT(Hyper-Threading Technology), one CPU acts like two
- doesn't actually work as fast as two, 15-30% performance improvement
- operating system must be written for HTT, windows XP and later

- run other operating systems within a single hardware platform
- virtualization added to the processor
- Intel Virtualization Technology (VT)
- AMD Virtualization (AMD-V)

- extend the functionality of your computer
- designed for end-user installation
- install hardware/driver, card or software for the operating system

- output of high-end audio, advanced headphone amp
- multiple inputs, music capture, podcasting, microphone

- many CPUs include an integrated GPU
- discrete graphics card is a seperate interface card for high performance

- video as an input
- live streaming, external cameras
- high performance, video bandwidths can be quite high
- PCI express connection

- Network Interface Card, ethernet connection
- motherboard may not include a NIC
- additional connections include servers, routers, security devices

- may need to install driver before installing hardware
- check for latest version, may need to uninstall previous drivers

- always check for good airflow
- motherboard layout is important
- component location is key among devices, wiring, and power

- designed to cool an entire adapter card
- can be bulky and may take additional adapter card space
- usually seen on high-end graphics cards

- 80mm, 120mm, 200mm for standard sizes
- different variable speeds and noise levels

- no fans, no noise
- video servers, TV set top box, satellite receiver, media server
- functions are controlled, carefully measured thermal tests
- low-power components

- copper or aluminum alloy to dissipate heat through thermal conduction
- fans and grid increase surface area, heat is then transferred to the cooler air
- gets very hot
- thermal paste between the chip and heat sink helps

- thermal grease, conductive grease
- place between heat sink and component, moves heat away from the component
- only a little is needed

- conduct heat without the mess, cut to size and install
- easy to use, won't leak
- almost as effective as thermal paste
- not reusable, remove and replace

- coolant is circulated through a computer
- used in automobiles and mainframe computers
- high-end systems, gaming or graphics, overclocking