BTEC Level 3 Unit 2

Computer Components

1

Stores:

The Operating System

Application files

User data

3.5 inch units in servers and desktops

2.5 inch units in notebooks and external drives

Computer Components 2

A typical hard disk today, would provide 250 GBs with an access time of 8.5 milliseconds, compared to 10 MBs and access times of 87 milliseconds in the 1980’s.

Hard Disk Video

Platter – “Is the actual disk”, made from aluminium or glass and are therefore hard/solid as apposed to floppy disks, the actual platter is not magnetic.

Coating – The Platter is typically coated in a magnetised (Iron-Oxide) material (Cobalt oxide in new disks), to allow it to store a magnetic pattern that will represent the computers data.

The future looks to be Solid State hard drives.

Computer Components 3

Platter/s 2 writeable sides, magnetic coating

Tracks Concentric circles

Sectors Typically 512 bytes

(smallest storage unit of the hard disk)

Cylinders?

Computer Components 4

Cylinders – when hard disks have more than one platter, the read/write heads are mechanically linked and are therefore placed over a set of tracks at any one time !

This collection of tracks is known as a cylinder.

Computer Components 5

Question – How many tracks are being read on the above image at any time?

A more recent permanent storage technology

Faster read and write access

Typically a 2.5 inch drive

Less power, heat and

No moving parts.

Can withstand more vibration.

More expensive than traditional drives.

4TB soon to be 8TB (SanDisk)

Computer Components 6

Three main standards:

PATA Parallel Advanced Technology Attachment

SATA Serial Advanced Technology Attachment

SCSI Small Computer System Interface

Computer Components 7

Principal interface for many years

Two drive controllers

IDE 1 or PRI IDE

IDE 2 or SEC IDE

Motherboards with SATA typically have one PATA for compatibility

One IDE (Integrated Drive Electronics) channel

supports 2 devices – a master and a slave

Computer Components 8

40 pin connector

80 wire shielded cable required for UDMA4 or better

Colour coded “cable select” cables avoid “master/slave”

How to cable?

Motherboard connector – blue

Master connector – black

Slave connector – grey

Pin 1 has a red stripe

Connectors are keyed

Computer Components 9

Record the manufacturer name, size (3.5/2.5) and capacity of the hard disks within the PC.

Is the drive IDE or SATA?

Is the drive connected to the Primary/secondary controller?

Is the drive configured as a master or slave?

Is the cable the correctly orientated?

we will later confirm this within the BIOS.

Computer Components 10

Hot Swappable

No Master and Slave configuration

Original standard support for 150 MBps and now 300,MBps, 6 gbps

Universal connector for 2.5/ 3.5 drives and servers

eSATA allows for external connection with 2M cable

Computer Components 11

Computer Components 12

Computer Components 13

•Parallel

•Serial

•Input/Output

•Male/Female

Cabling

•Twisted pair

•Coaxial

•Optical

Identify the ports pictured beneath.

Computer Components 14

RAM – Random Access Memory

ROM – Read Only Memory

Cache – Fast memory that does not need to be refreshed. L1Cache

L2 Cache

L3 Cache

Computer Components 15

L1-cache

The fastest cache and it usually comes within the processor chip itself.

L1 cache typically ranges in size from 8KB to 64KB and uses the high-speed SRAM (static RAM) instead of the slower and cheaper DRAM (dynamic RAM) used for main memory.

The Intel Celeron processor uses two separate 16KB L1 caches, one for the instructions and one for the data.

L2-cache

Lives between L1 and RAM (processor-L1-L2-RAM) and is bigger than the primary cache (typically 64KB to 4MB).

L3-cache

Not found nowadays as its function is replaced by L2 cache. L3 caches are found on the motherboard rather than the processor. It is kept between RAM and L2 cache.

Computer Components 16

SDRAM – Random Access Memory

This is where software and programs once loaded are stored (re-open application).

When the CPU runs a program it fetches data from the RAM.

RAM is volatile – which means it can be, changed destroyed ,deleted and replaced when needed.

Currently a DIMM format

Sizes of DDR2 2GB (8GB) to DDR4 64 GB (128GB).

Computer Components 17

Identify the location of the RAM inside the given PC

Remove the RAM, identify the RAM size if possible by reading the label.

Check for notches , align RAM, reinstall the RAM.

Using CPUz identify the amount of RAM within the college computers in T104.

How many RAM slots are there on the motherboard?

What is the current size of RAM memory inside the PC? (the motherboard manual will typically confirm the maximum size).

Computer Components 18

Basic Input Output System

Firmware located on the Motherboard that is loaded when the computer is first switched on.

Identifies and checks the system hardware

Carries out POST (Power On Self Test)

Prepares a system to boot an Operating System.

Many types exist, Phoenix, Award, Ami , etc.

An example of a ROM (EEPROM)

Computer Components 19

A replacement for the BIOS system, yet supports BIOS services.

UEFI is a specification detailing an interface that helps to hand off control of the system for the pre-boot environment (i.e.: after the system is powered on, but before the operating system starts).

Benefits include:

Support for new standard such as iPV6 (iPV6 network boot - iSCSI, PXE)

Improve boot graphics (Safe Mode Video)

New authenticated boot scenarios

32-bit protected mode as being a native mode of operation– Support for > 2TB hard diskComputer Components 20

Specialised cards (generally PCI or PCI-e bus)

Networking

Sound

Additional ports

Considerations

Bus type

Free Space

Device Driver (correct software)

Computer Components 21

How to remove and install an expansion card?

Blanking plates

Screw or retain the card

Ensure the card is found by the Operating System.

Computer Components 22

which processor cache is quickest to fetch/store data L1 or L2?

How much cache can be found on a typical AMD Quad core processor?

Which other PC component also includes a cache?

What memory type is the fastest -SRAM or SDRAM?

Modern RAM is found in which format DIMM or SIMM or Rambus?

Explain the term “firmware”.

Computer Components 23

Introduce assignment

Part 1 can now be completed.

Computer Components 24