Computer Hardware Preview the exam questions. RAM SECONDARY STORAGE CPU

COMPUTER FACTS  A computer is an electronic device which works within a binary digital system and has 4 functions: –Accept input ( data – isolated facts ) –Process input ( data ) –Produce output ( information – processed data ) –Storage

Binary Digital System A system that works with two states. For the computer these two states are on/off or the digits of 1 and 0.

Tower CPU RAM BUS Hard Drive Floppy CD Drive Ports printer mouse Monitor keyboard Peripheral devices

Some Hardware Definitions  Tower – box that holds CPU, RAM, etc.  Peripheral Devices – input/output devices such as the printer, monitor, etc.  Bus – electronic device that connects all the internal parts of the computer  Port – connectors for all peripheral devices MAIN MENU

CPU Central Processing Unit Diagram of parts Diagram of parts FFAACCTTSSFFAACCTTSS How does this work? MAIN MENU

Control Unit ALU Registers MAIN MENU

CONTROL UNIT Fetches and Interprets Instructions From RAM MAIN MENU

ALU (arithmetic/logic unit) Executes instructions MAIN MENU

Register Fast accessing storage Inside the CPU MAIN MENU

CPU FACTS  Megahertz – unit of speed for the CPU  CPU works with the machine cycle machine cycle machine cycle  How are numbers, letters, graphics etc. represented in binary digits contained in registers? How are numbers, letters, graphics etc. represented in binary digits contained in registers? How are numbers, letters, graphics etc. represented in binary digits contained in registers? MAIN MENU

MACHINE CYCLE INSTRUCTION 1. Fetched 2. Interpreted 3. Executed

What part of the CPU fetches, interprets, and executes? Fetch Interpret Execute CPU Control Unit ALU

RAM Random Access Memory FACTS How does this work? How does this work? Physically a series of chips. Storage Units MAIN MENU

RAM FACTS  Holds data and instructions waiting for processing by the CPU  Temporary storage  Contents are deleted when power source removed.  What is CACHE? CACHE? MAIN MENU Click to view facts.

CACHE  Cache is fast accessing intermediate memory that holds the most needed data and instructions.  It is smaller than RAM.  Because it is smaller than RAM a search of cache is faster memory access.  Therefore it is always searched first when available.

CPU CACHE RAM

BIT = smallest unit of storage binary digit; 1 or a 0 BYT E = 8 bits KILOBYTEMEGABYTEGIGABYTETERABYTEBYTE = 1,000 bytes = 1,000,000 bytes = 1,000,000,000 bytes = 1,000,000,000,000 bytes MAIN MENU

SECONDARY STORAGE DISKS/DRIVES Floppy Drives Hard Drives CD Drives MAIN MENU

All secondary storage has 2 parts: A disk – a platter which stores the data/inforamtion A drive – mechanism which reads the disk NOTE: a read/write head is part of the drive which sits over the disk and read the data

A CRASH is when the read/write head touches the disk and destroys data.

All Disks have two parts: SECTOR S TRACK S

All Disks have two parts: This makes an Addressable Space. Therefore, Disks are Randomly Accessible.

Hard Drives  Composed of several disks.  Large, permanent storage.  Not portable storage.  Disks are magnetic.

Floppy Drives  Composed of one disk.  Large, permanent storage.  Portable storage.  Disks are magnetic.

CD Drives  Composed of one disk.  Very large, permanent storage.  Portable storage.  Disks work with light waves.

Graphic Resources  Basics.htm  members.iweb.net.au/~pstorr/ pcbook/book2/memchips.htm  1/computer-parts/ computer-parts- n...  webhome.idirect.com/~jadams/ electronics/identify2.htm 