Hardware: SAS Flashcards
(100 cards)
1
Q
What is a super computer?
A
Most powerful + expensive computers available today.
2
Q
What is a server?
A
Computer used as the central computer in a network. A rack server might be used by a large business/school.
3
Q
What would a lack of RAM do?
A
Slow the computer when editing a large video file.
4
Q
What is CPU speed measured in?
A
Hertz.
5
Q
Why is it important to update computer’s anti-virus?
A
Protect against new malware. A worm is a type of virus.
6
Q
What does an OS do?
A
Controls overall computer function + allows hardware to interact with applications.
7
Q
What is a browser?
A
Application used to navigate internet.
8
Q
What is a computational thinker?
A
Someone who thinks/expresses solutions like a computer.
9
Q
What is a PC?
A
Specifically related to original IBM PC (1981) concept. New systems were referred to as IBM compatible + many PC terms refer back to IBM PC, PC/XT, PC/AT.
10
Q
What is in PC?
A
Motherboard, processor (Intel compatible), memory, storage devices (HDD, DVD, CD, FDD), keyboard, video, mouse (KVM), operating system.
11
Q
What is the processor?
A
Central Processing Unit (CPU), ‘engine’ of PC.
12
Q
What is the PSU?
A
Power Supply Unit. Converts AC supply to DC supply for PC, good PSU helps voltage regulation, eliminating mains supply spikes + surges. Rated in wattage, more powerful = more watts. Also cools. Reduces high voltage to lower voltage for buses.
Better not to buy cheap PSU, high quality provides clean, stable power + low noise/heat. PSU fan works hard + often spindle bearings break down. PC noisy, so may replace when this happens. Failing HDDs become noisy so ensure it’s PSU, not HDD. Try powering up w/out HDD connected to check.
Modular ports allow you to attach cables that carry power to components. Modular means you only have to attach cables for components you have. Fan expels hot air as PSUs gen lots of heat.
PSU takes power from wall socket. PSUs rated from 200W to 1600W so must ensure you have enough wattage.
8 pin ATX carries power from PSU to CPU. 24 pin ATX carries power from PSU to motherboard. 6 pin Express carries power from PSU to HDD.
13
Q
What is memory?
A
RAM is primary memory, holds programs + data used by CPU.
14
Q
What is MIPS?
A
Millions of Instructions per second. Method of measuring raw speed of CPU. Higher clock speed + more cores makes computers faster (more MIPS).
15
Q
What are removable media drives?
A
Floppy Disk Drive/FDD (simple inexpensive removable, now only external option), Optical Drives (CD, DVD, BD/Blu-Ray), USB Flash Drives + SD Cards.
16
Q
What is storage?
A
Hard Disk Drives/HDD (Primary archival storage media, refers to both disk + mechanism controlling positioning, reading + writing to & from it), cables, sockets + connectors (IDE, SCSI, SATA, DC power, all keyed for correct connection)
17
Q
What are hardware components?
A
Video, audio + comms ports – Embedded graphics adaptors + sound adaptors, graphics cards & sound cards, display ports (VGA, DVI, HDMI), keyboard + mouse ports, parallel, serial, universal bus ports (USB)
Displays/Monitors: Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Thin Film Transistor (TFT), projectors.
18
Q
What are the 4 functions of BIOS?
A
POST (Power On Self Test), Set-up (Configure motherboard/chipset settings), bootstrap loading + BIOS (Basic Input/Output System)
19
Q
What is POST ?
A
Power On Self Test. Press power button, motherboard sends signal to PSU to start (PSU fans start if present), alt current stabilised for devices (taken down to 12V). When PSU power output stable, sends ‘power good’ signal to motherboard, components begin to power up + power LED comes on. During POST, see + hear activity on Disk drive LEDs, keyboard & mouse. POST also tests CPU, memory configs, IO devices + ports. POST checks RAM by writing & reading data, monitor displays this progress. Initialises on-board devices. POST tests your computer’s processor, memory, chipset, video adapters, disk controllers, disk drivers, key boards, and other components.
20
Q
What are beep codes?
A
Beep Codes: Bios manufacturers (AMI, Phoenix, Intel) have diff codes, defined in doc in each system. Successful POST gens 1 beep (except on Compaq, 2 beeps).
21
Q
What is a cold boot?
A
Mains power has just been supplied to PC.
22
Q
What is a warm boot?
A
Power on + booting process restarted (ctrl, alt, del) e.g. completing installation/windows updates. Does mini POST, RAM not tested, BIOS determines which boot by checking address in memory.
23
Q
What is the power switch?
A
Turn on power supply, physical switch on PSU.
24
Q
What is the power button?
A
Button on case connected to pins in motherboard.
25
How does CPU initialise itself?
Resets internal registers, then jumps to start of ROM BIOS program + executes it. Instruction there executes POST before trying to boot OS.
26
What does BIOS do?
Manages basic config as defined in CMOS memory. Access to BIOS setup utility via password to protect user settings. Most systems use F1/F2/DEL during powerup. During bootup, basic utility drivers (programs) for keyboard, mouse, disk drives + vids loaded from BIOS. Newer comps have fancy BIOS (e.g mouse driven) or have OS (Apple). BIOS info preset by manufacturer + user configurable as required. BIOS has 2 passwords (user/system + supervisor/setup) If password forgotten, reset CMOS) Can lock BIOS to stop OS installs etc.
27
What is CMOS?
Complementary Metal-Oxide-Semiconductor. CMOS mem contains all PC details (number, type + size of disk drives, mem size, which disk drive OS loaded from). Most displayed on screen. Small battery used to maintain CMOS content. RTC (Real Time Clock) as power real-time-clock chip. Battery failure can cause info loss + booting issues. Windows + Anti-virus updates also not applied as they check date. Indicator of this is date + time errors. CR2031 battery commonly used. CMOS memory contains basic system config.
28
How can you reset CMOS battery?
Jumper (short) 2 pins on motherboard or remove battery. Can clear CMOS: turn off peripheral devices connected to comp, disconnect power cord from AC power source, remove comp cover, find battery, remove battery, wait 1-5 mins, reconnect battery, put comp cover back on.
29
What is bootstrapping?
Loads master boot record (MBR) from boot disk, MBR code checks drive has valid partition table. If ok, MBR loads 1st bootable partition (volume boot record), checks this & runs code.
30
What is true of BIOS versions?
Most have flash BIOS, can be updated as necessary. Can check BIOS date + version (system info). Regular BIOS updates provided by manufacturer. Updates/patches to support latest devices (processors, HDDs, new network cards). Updating BIOS can fix bugs/add features, get from MOTHERBOARD manufacturer, not BIOS manufacturer.
31
How might you update BIOS?
Windows executable, BIOS setup, bootable media, emergency flash BIOS. Possible to brick comp, some systems have 2 BIOS chips.
32
What are the limitations of BIOS?
Max size restricted, restricted ability (16 bit instructions), hard-disk type restricted, can only boot from MBR formatted HD (limits max size to 2.2Tb), replaced by UEFI (Unified Extensible Firmware Interface).
33
What is a motherboard?
Heart of PC, all components in PC, CPU, Memory, keyboard, mouse, video + peripherals linked here. Characteristics of form factor + chipset. Motherboards have varied I/O requirements + connections, speed of change means new ports coming constantly, hard-wiring ports into case for all connections inflexible + unfeasible. Back of case has ‘open slot’ so motherboard pokes ports through, protected by I/O shield which comes with motherboard.
CPU Socket is where CPU sits, it has shield that holds in place. Front panel headers are where you attach all ports + buttons on case to motherboard.
There are RAM slots where RAM goes, only allow 1 type of RAM, most motherboards have between 2 and 8 slots. IO ports are where you plug in peripherals.
Motherboards need enough power to run components attached to them so usually have more than 1 connector to PSU. Motherboard screwed into case using standoffs which hold it away from metal of case. HDD SATA (serial ATA) port, hard drive connects here. Provides connectivity between processor + expansion slots.
34
What is form factor?
Defines physical properties (size, layout, power, mounting hole positions, connector types). E.g. AT (12 X 13.8”), Baby AT, BTX (12.8 x 10.5), Micro BTX (10.4 x 10.5)
Cases come in multiple sizes + shapes (form factors) each designed to accept specific motherboard form factors + PSU. Main sizes: Tower (takes ATX, uATX, mini-ITX boards), Midi tower (ATX, uATX, mini-ITX boards), Mini tower (uATX, mini-ITX boards), Desktop/Low Profile (uATX, mini-ITX boards).
35
What is chipset?
Define which CPUs supported, speed + type of RAM used + interfaces supported. Chipset defined in 2 sections: Southbridge & Northbridge (Intel MCH & ICH)
36
What is the Northbridge chip?
Interface CPU with mem + graphics.
37
What is the Southbridge chip?
Looks after bus + peripheral interfaces.
38
What are the issues with cases?
Case reduces EMF interference to/from PC, full height PCI card won’t fit low profile case, tower most suitable for floor standing, not desk, for cooling, always keep slot panels installed so keep when installing PCI cards etc, ‘screwless design’?, lockable?, quality.
39
What do filters do?
Protect against mains power surges.
Over voltage: internal components protect against over-voltage (short time).
RFI filtering: ferrite cores suppress radio frequency emissions.
Surge protection: clamp voltage, clamp speed, energy absorption/dissipation.
40
What is UPS?
Uninterruptible power supplies. Includes battery/batteries to maintain power in event of power outage. Keeps PC running so data saved + normal shutdown implemented. Protects against mains surges + dips (brown outs). Many provide software tool to provide shutdown procedures in case of power failure while users away i.e. tools for monitoring UPS state + mains supply state.
41
What are PCI slots?
High speed connected to motherboard for PCI cards. Most common PCI cards are graphics cards but can also be Wi-fi or sound.
42
Describe CPU.
Pins plug into socket on motherboard, each model has own layout + orientation in socket.
Processor/Die is chip that does all calculators. Very delicate + tightly packed so gets hot quickly.
Heat plate attached directly to processor, quickly gets CPU’s heat away to CPU cooler. Add thermal paste to CPU to improve conductivity between it and cooler.
43
What is CPU cooler?
Fan blows through fins to move hot air away from heatsink.
Bracket attaches cooler to motherboard, each CPU model has own bracket size + shape.
Cooler plate makes contact with CPU through thermal paste, made from highly heat conductive material (usually copper)
Heatsink fins give large SA for CPU’s heat to be dissipated.
Power cable plugged into dedicated CPU fan socket on motherboard.
44
What is graphics card?
Graphics processor at heart of GPU turns instruction from CPU into something seen on screen.
Many GPUs use connector to allow multiple cards to be linked together for more power, some up to 4. Has fan + heat sink.
PCI connector fits into PCI slot of motherboard + most motherboards have dedicated PCI slot for GPUs.
Back plate sits in rear of case + contains connectors that go to screen (HDMI/display port)
45
What is RAM?
Memory chips on RAM stick are very fast types of memory designed to hold programs so comp can access v. quickly.
RAM connects to motherboard with special connector. Each RAM type has special notch cut out so you don’t put wrong types together.
Motherboard RAM slots have locking switches that hold RAM in place.
46
What is hard drive?
Has spinning disc, faster it spins, faster data accessed.
| SATA + power connectors used to connect HDD to motherboard (SATA) + power supply.
47
What is case fan?
Fins control which way air moves, look for arrow on side of fan to show which way fan blows.
Many fans + motherboards support variable speeds so ram only runs as fast as it needs to.
48
What is hard disk?
Records onto magnetic coated glass/aluminium circular disks/platter arranged in layers. Small gap between each layer for read/write heads to move from edge to middle of platter. Each surface has own read/write head.
49
What are HDD specs?
Capacity, seek time (ms), rotation speed (rpm), cache/buffer, power consumption, data transfer rates (ext, int (read/write speed))
50
What are SSDs?
No moving parts, mainly use NAND flash, v.fast transfers, block erase, wear levelling, over provision, faster I/O but limited lifespan. G-sensor locks hard drive if you drop laptop, tracks angle.
51
What are hard drive interfaces?
PATA/IDE (Parallel Advanced Technology Attachment/Integrated Drive Electronics), SATA (Serial Advanced Technology Attachment), mSATA (mini SATA), M.2, SATA Express, SCSI, SAS.
M.2: Diff widths (mainly 22mm), diff lengths (16, 26, 40, 48, 60, 80, 110mm), diff heights (S1, S2, S3, D1, D2, D3, D4, D5), diff signalling (SATA3 w/ AHCI, PCIe w/AHCI, PCIe w/ NVMe).
52
How might you deal with disk failure?
Via backups + duplicate servers (have interruption) or lights-out tolerance (RAID).
53
What is RAID?
Redundant Array of Inexpensive Disks (RAID 0 – Striping, RAID 1 – Mirroring, RAID 5 – Stripe w/ parity)
Flash memory units are solid state storage devices used for easy + fast info storage, more akin to HDD than RAM. Retain data when power removed.
54
What are flash drives?
Has USB connector, USB mass storage controller device, test points, flash memory chip, crystal oscillator, LED, write-protect switch + unpopulated space for 2nd flash memory chip.
55
What are flash cards?
Most defunct (CompactFlash, SmartMedia, xD, MemoryStick), SecureDigital won.
56
What are removable disks?
Floppy disk drive, super floppies, optical drives (CD-ROM, DVD, Blu-Ray).
57
What are optical disks?
Use lasers on discs coated w/ aluminium substrate, writing creates indents to form on substrate, in read mode laser beam reflected off surface + detected by photoelectric cell & read in series of binary nums. 1 physical track from centre to edge as opposed to FDD & HDD which use concentric tracks.
58
Describe processors.
Current Intel: Celeron, Pentium, Core i3, Core i5, Core i7, Core i9.
Intel + AMD keep leapfrogging each other in terms of power.
59
What are processor criteria?
Clock speed, Widths (data bus, address bus, internal registers), cores, power consumption, cache, features (HyperThreadingTM, GPUs, virutalisation support), cost. *Measured by OPS, FLOPS, MIPS
60
What is a process?
Self-contained series of execution w/ own allocated memory. Indep context of execution i.e. program. You have written a Hardware practical report, contacted your class mates via Teams to complete it and submitted it in Canvas, this would be processes in terms of processor multiple execution.
61
What are threads?
Linked series of execution within overall process, share mem/resources w/process + each other, multiple threads of execution within context of process. i.e. 1 program doing multiple things at once.
Early comps looked like they did many things at once, just quick at switching between processes. Each CPU can be working on process: one context. CPUs pick up waiting processes. You have made calculation and plotted graphs in Excel, this would be threads in terms of processor multiple execution.
62
What is multiple execution?
Multiple execution: hyperthreading, multiple cores. (multiple cores w/ hyperthreading poss)
63
What is hyperthreading?
Intel tech, CPU runs multiple threads within single process at same time, multi-threaded apps sped up significantly, no overhead of context switching (same mem address)
64
What is multiple cores?
Single CPU unit w/ cache/IO features, simultaneously execute more than 1 context, similar to having multiple CPUs but no overhead – cheaper.
65
Describe heatsink.
Must be maintained as noisy fan & dust.
LGA sockets used by Intel, ZIF sockets (AM/FM) used by AMD.
Heat sink retained fitted around CPU socket, processor inserted in snap to fit socket, thermal grease used to ensure good heat dissipation, heat sink added + retained used to clip in tightly against processor.
66
What are types of memory?
ROM, RAM (SRAM, DRAM). Flavours of DDR (DDR, DDR2, DDR3, DDR4)
67
What is static RAM?
Uses flip-flops to store data, keeps data as long as there’s power, v.fast, bulky, used in cache of CPU.
68
What is dynamic RAM?
Capacitor stores data, slowly loses charge/data, more compact than SRAM, must be refreshed, diff types (Synchronous RAM (SDRAM), Double Data Rate SDRAM (DDR))
69
How does motherboard improve mem performance?
Uses dual channels w/ DDR/DDR2/DDR3 DIMMs. Mem controller can comm w/ 2 DIMMs at same time, doubling mem access speed.
To use dual channel config, need motherboard w/ feature + 2 identical mem modules per channel. Dual channel mem slots usually colour coded on motherboard.
70
How do you upgrade RAM?
Need to know type of DIMM PC can take, how many DIMMs it can take, how much mem in slots, how much mem soldered to board, max RAM supported by processor/chipset + max RAM supported by BIOS.
71
What is server class memory?
ECC (error-correcting code), buffered RAM.
At start, single parity bit for each byte, could detect single bit errors + couldn’t fix them. ECC (error check + correct) uses extra 8 bits for 64 bit word, can correct single bit error in 64 bit word, can detect double bit errors but not fix, needs CPU, motherboard & mem support.
72
What are the symptoms of dead memory?
Blue screen of death, random page faults, wrong mem report.
For Windows Mem Diagnostics, Event Viewer > Windows Logs > System Log
Can use Memtest86+. Swap + Test strategy, take out all DIMMs, test each individually in faulty system. If 1 fails, bingo. If all fail, motherboard problem.
73
What are expansion bus slots?
Have been feature of PCs since original IBM PC in 1987. Allow extra functionality to be added to system. Earliest expansion buses’ standards + principles apply in modern systems. Operates own clock speed, sep to CPU.
74
What is criteria of expansion bus slots?
Criteria are physical connection (must fit slots provided), communication (how to talk to CPU) + drivers (software to access card functions).
All devices in PC, incl. expansion slots need to connect to external data bus + address bus to select + process data. Chipset enables/makes these connections so card installed in expansion slot functions as part of motherboard, expansion cards can’t use PC system clock though. Otherwise, card would be required for every possible motherboard speed to synchronise with motherboard (RAM, CPU, etc).
75
How do we cater for expansion cards since they can't use PC system clock?
Use of sep timing device, called expansion bus crystal. All expansion cards run at same speed on motherboard. Section of chipset acts as go between for system bus + expansion card bus. All cards attached to same underlying circuitry in parallel buses.
76
What is EISA?
Reasonably successful in server market, better suited to bandwidth-intensive tasks (disk access + networking).
77
What is PCI?
PCI (peripheral component interconnect) is 124 pin connector, displaced ISA as standard I/O bus, connects directly to enter Southbridge chipsets rather than via Bus controller chip/DMA, faster than ISA.
PCI express board-edge connector available in num of diff sizes, depending on PCI express lane width from x1 to x16. X16 replaces AGP slot on motherboards, for graphics board expansion.
78
What is PCI-X?
PCI-X is enhanced version of PCI bus, 64 bit so uses larger connector, PCI cards can run in PCI-X slots.
32-bit PCI card has 124 pins for mating with slot on motherboard, fits into 32 or 64 bit slot. 64-bit PCI card has 184 ouns for mating with slot on motherboard, fits into 32 or 64 bit slot. Signal pins 63-94 only used on 64-bit PCI bus cards, PCI pin out for 32-bit bus stops at key-way while 64-bit pin out occupies entire table. When installed in 32-bit slot, data transfer on 64-bit card limited to 32-bit.
79
What is AGP?
AGP is accelerated graphics port. Video performance requirements continue to drive development of interface provision, graphics bus transitioned from PCI to AGP, AGP to AGP2X, AGP4X, AGP8X. AGP8X operates at 2.134 GB/s. AGP development reached peak so extending AGP bus more difficult & expensive as frequencies increased.
Specifies 2 keys (3.3V key & 1.5V key). AGP cards backward & forward compatible but within limits, 1.5V only keyed cards won’t go into 3.3V slots & vice versa. Some cards like nVidia’s GeForce 6-series/ATI’s X800-series only have keys for 1.5V to prevent them from installing older motherboards w/out 1.5V support.
80
What is PCIe 1.0?
PCIe 1.0 uses existing PCI programming concepts, high-speed serial link, point to point (not single bus), single lane carries 250Mb/s, can combine many increases to increase throughput, hot-pluggable (if motherboard supports it).
81
What is PCIe 2.0?
PCIe 2.0 doubles PCIe transfer rate, backwards &_ forward compatible. PCIe 2.0 x 16 allowed Nvidia develop scalable link interface (SLI). With SLI, dual GPUs used for video processing, motherboard must have 2 PCIe x16 2.0 slots, best to use identical graphics cards.
82
What is PCIe 3.0?
PCIe 3.0 doubles speed throughput, slight change in encoding 128b/130b.
PCIe 4.0 to come as of 2018.
83
What are I/O Addresses?
I/O Addresses are how CPU talks to expansion cards (& other devices) using unique addresses for each, as it does w/ RAM. Each card has 4 I/O addresses + no 2 devices can share I/O address. Fixed standards for some address values (primary IDE channel is 01F0-01F7)
84
What is IRQ?
Interrupt Requests (IRQ) is means whereby device can inform CPU that it needs attention, controlled by part of Southbridge circuitry known as I/O advanced programmable interrupt controller (IO APIC). IO APIC has direct connection to CPU, once alerted device wants attention, CPU queries IO APIC to see which device needs attention.
85
What is DMA?
Direct Memory Access (DMA) is means by which bus devices can exchange data w/ memory w/out CPU being involved, thereby freeing CPU for other tasks. In 16 bit ISA buses there were 8 defined DMA channels. DMA required DMA controller in same way as IRQ uses IO APIC. DMA still supported on modern systems, but process known as blue mastering in which devices manage DMA w/out use of DMA controller is standard. Process also known as ultra DMA/ultra-ATA/133 only used by ATA/IDE devices to move data directly to/from RAM at high speed.
86
What is PnP?
Plug + Play (PnP), PCI doesn’t support DMA + enabled intro of PnP devices, prior to PnP, devices had individual DIP switch banks that had to be set accordingly, PnP managed by Windows OS which detects device, determines & allocates hardware resources required.
When adding cards, know card (fits? Have drivers for OS?), fit card, install drivers + verify it works.
87
Describe BIOS.
BIOS: It manages data flow between the computer's operating system and attached devices such as the hard disk, video adapter, keyboard, mouse and printer, built-in core processor software responsible for booting up the system + It is the program a personal computer's microprocessor uses to get the computer system started, held on a chip on the motherboard, and it starts everything for the computer. UEFI provides spec for a different software interface for boot and runtime services. BIOS Order is POST, Setup, Bootstrapping, BIOS.
BIOS acts as basic interface between the OS and your hardware when the system is booted and running.
88
Describe setup.
Setup enables you to configure the motherboard and chipset settings along with the date and time, passwords, disk drivers, and other basic system settings.
89
How do you enter BIOS setup utility?
To enter BIOS setup utility, start up computer, press key (F1, F2) on keyboard before BIOS hands over control to Windows.
90
What does form factor define?
Form factor defines size, layout and connector types of the motherboard. Ethernet connection is defined by chipset factor. I/O Shield comes with motherboard.
91
Describe hard disk.
Hard disk spins v. quickly, up to 15k rpm, is read and written to by head, is called spinning platter hard disk, is a physical spinning disk + each of these platters is a magnetics read-writeable disk. Usually a sealed unit + not a user-serviceable part.
92
Describe PATA.
PATA allows you to connect 2 drives to one cable.
93
Describe RAID.
RAID is standard way of using multiple discs to use present 1 logical drive.
94
What are flash drives?
Flash drives are solid state devices.
95
What is order of hard drive interfaces created?
PATA, SATA, mSATA, m.2.
96
What is AMD like?
AMD gets very good graphics performance without a discrete graphic card.
97
What is FLOPS?
FLOPS is unit of measure for the numerical computing performance of a computer.
98
How does heatsink work?
Air is put through Heatsink with case fans, air is put through Heatsink with a dedicated CPU fan, in early 80s CPUs did not need heatsinks, because they didn’t run so hot + main purpose of Heatsink to take the heat and get it away from the processor.
99
Describe PCIe lanes.
Each lane in PCIe x4 handles data simultaneously forwards + backwards. PCI lane can be replicated many times, each lane carries 250MB/s.
100
What are drivers for?
Ensure user can access features & functionality of expansion.
