Download Computer Hardware 01/26/00

Computer Hardware
Computers and
components
Basic Computer System
Processor
ALU
CNTL
.....
BUS
Interconnections
I/O module
CONTROLLER
MAIN MEMORY
BUS
ATTACHED
DEVICE
Computer
Components
CPU Cycle
Increment Program Counter
Start
FETCH
FETCH
EXECUTE
EXECUTE
Halt
Execution Cycle
Instruction Sets
Complex (CISC) or Reduced (RISC)
INSTRUCTIONS
ROM
CNTL
ALU
.....
Measuring Processing
Power
Clock Speed
Instruction Speed
Word Length and Bus Width
Speed of Arithmetic
Instruction Set
Pipelining
Primary Storage
Volatile
DRAM
SRAM
Cache
Nonvolatile
ROM
Measuring Storage (bytes)
Kilobytes
KB
1,000 B
Text document
Megabytes
MB 1,000,KB
Images
Gigabytes
GB 1,000 MB
Hard disk drives
Terabytes
TB
Trillions
Data warehouse files
Attached I/O Devices
Secondary Storage
DASD
Tape
Removable
Electronic Storage
Optical (etc.)
devices
Communication
Devices
Modems and
Codecs
LAN’s, Backbones
and WAN’s
Routers and other
node devices
Secondary Storage
Devices
Fixed Media
hard disks
RAID
Removable Media
diskette
laser-servo diskette
cartridge disks
tape
CD-ROM
flash memory
Attached Devices
Hardware: device itself such as a disk or
video display device.
Electronics: controller that communicates
with the device
Software: device driver that is loaded
into the computer operating system
Local and Peripheral
Bus
Data Transfer:
MAIN MEMORY
DBUFFER
A T A
CHANNEL
CPU
CONTROLLER
DASD
I/O Controller (DASD)
REGISTER
PROCESSOR
REGISTER
REGISTER
BUFFER
Direct Access Storage
Device (DASD)
DASD Structure
Read-Write Heads
Cylinder/Track/Block
Track
Block (Sector)
Cylinder
Disk
Organization
Data Storage
FAT (File Access Tables), Directories and
Catalogs
Update and Delete
Fragmentation and reorganization
Blocks, Headers and Interblock Gaps
Hardware II
General Purpose Computing
Software primacy
Applications are controlled by changing the
instructions run by the computer, rather than
by changing the hardware
ASIC’s and Firmware
Any program that can be written in software
can also be burned onto a chip as a family of
circuits
Computer Classifications
Size
mainframe
midrange
microcomputer
Function
legacy
mainframe
server
router
client
Mainframe
(Legacy)
Tuned for transaction
processing
Has channels to support
very large numbers of
attached devices
Runs a mainframe
operating system
Tend to support legacy
software
Client/Server Architectures
FAT CLIENT
FAT SERVER
SERVER PROCESSING
CLIENT PROCESSING
CENTRALIZED
STAND-ALONE
Client/Server Architecture
An architecture in which the client
(personal computer or workstation) is the
requesting machine and the server is the
supplying machine, both of which are
connected via a network.
Client/Server Architecture
Client
May do some or all of
the processing
Requests services
from the network
Server
Contains data and
may contain
programs
Server downloads
information
(applications or data)
to the client for
operation
Client
Use relatively inexpensive
computer chips (Intel or
Motorola)
Have a single processor
Optimized for user
convenience
Single user
Limited numbers of
attached devices
Server
Use inexpensive CPU
chips
Designed with
redundant components
Have large internal
memory capacity
May not need very fast
CPU capability
Three Tier Client/Server
Any time
Any place
Any way
Router
Used to segment networks and prepare
message packets for transmission
Special purpose operating system to read
and forward message packets
May support firewall functions
Support special purpose CPU chips and
optimized network sysems
Routers
From A
From B
Input Buffer
Input Buffer
Input Buffer
Processor
Output Buffer
Output Buffer
Table of
Addresses
To C
To D
Central Architecture
Client/Server
Web Access