System Memory Memory is a large array of words or bytes, each with

System Memory

Memory is a large array of words or bytes, each with

its own address. It is a repository of quickly accessible

data shared by the CPU and I/O devices.

Main memory is a volatile storage device.

Built up using Dynamic RAM (DRAM)

Synchronous DRAM

Primary cache (Level 1) is on the CPU

Secondary cache (Level 2) supplies stored info to

processor without any delay

Secondary Storage Management

Since main memory (primary storage) is volatile and too

small to accommodate all data and programs permanently

the computer system must provide secondary storage to

back up main memory.

Most modern computer systems use disks as the

principle on line storage medium, for both programs and data.

CD-ROM can be recordable/rewritable

DVD large capacity successor to the CD

Tape Backup

Removable Storage

Microprocessor (CPU)

• John von Neumann’s architecture:

Central Arithmetic unit, Central Control unit, Memory, I/O devices

• All the elements of a CPU (registers, ALU, primary cache, execution unit,..) stay in step by a clock which dictates how fast it operates

• Pipelining: at any one time one instruction is being loaded, while an other is being executed

COMPONENTS

• Motherboards

• Processors

• Chipsets

• Interfaces

• System Memory (main memory), others– Primary cache (CPU)– Secondary cache (bridge processor-memory)

Interfaces

• Buses– Fastest bus connects primary cache with CPU chip– Dual independent (memory and level 2 cache)– ISA bus: I/O Bus system– Expansion bus for additional components– PCI bus: Local Bus standard– Accelerated Graphics Port (AGP): Frontside bus

Motherboard

• Main circuit board – Input/Output System (BIOS) in ROM– The Baby AT (BAT) format reduced the

dimensions of the motherboard

– Intel Advanced/ML (ATX)

– LPX is a specialized Baby-AT used in low profile, loose spec desktop PCs

– NLX is Intel’s improved LPX