1. Chapter 2

2. Module 2A Inside the System Unit
Module 2B Data Storage
Module 2C Input and Output
Chapter 2

3. Inside the System Unit Talking about Computer Hardware
The System Unit: Looking Under the hood
How Modern Computers Represent data
The CPU: The Computer’s “Brain”
Microprocessors: Computers on a Chip
Comparing CPUs
Memory: The CPU’s Electronic Scratchpad
Buses: Freeways for Data
Module A

4. Talking about Computer Hardware
Inside the System Unit
Talking about Computer Hardware
Module A
Computer and peripherals

5. The System Unit: Looking Under the Hood The system unit, exposed A
Inside the System Unit
The System Unit:
Looking Under the Hood
Module A
The system unit, exposed

6. How Modern Computers Represent Data
Inside the System Unit
How Modern Computers Represent Data
Digital versus Analog Representation
digital: high and low power signals
analog: continuous variable scale
Numbering systems
every numbering system has a base
Module A

7. Inside the System Unit
Binary Numbers
Module A
A binary number is called a binary digit, or bit. A bit is the smallest unit of information that a computer can work with.

8. Inside the System Unit
Counting
Module A

9. ASCII & EBCDIC Originally used a total of 7 bits
Inside the System Unit
ASCII & EBCDIC
Originally used a total of 7 bits
encodes a total of 128 characters
included letters, numbers & punctuation
Looking for a wider market
IBM and Apple expanded to 8 bits
extended character sets not standardized
Macintosh and PC versions differ
Module A

10. Representing Data Unicode Parity Representing numbers
Inside the System Unit
Representing Data
Unicode
expanded to 16 bits (65,000 characters)
can represent most languages
Parity
extra bit added to coding systems
used to ensure code stored correctly
odd and even parity
Representing numbers
floating point notation
Module A

11. The CPU: Looking Under the Hood System Clock Instruction set
Inside the System Unit
The CPU:
Looking Under the Hood
System Clock
determines speed of the system
Instruction set
list of instructions
Four-step process (machine/processing cycle)
Arithmetic-Logic Unit (ALU)
arithmetic & logical operations
registers are temporary storage
Module A

12. Microprocessors: Computers on a Chip
Inside the System Unit
Microprocessors:
Computers on a Chip
Module A
CPUs in most computers designed for individuals are microprocessors, which are complete CPUs (control unit and ALU) fabricated on a single chip of silicon.

13. CPU Compatibility Compatibility Downwardly Compatible CPU Sockets
Inside the System Unit
CPU Compatibility
Compatibility
a program that can run on a computer
Downwardly Compatible
run programs designed for earlier chips
CPU Sockets
physically holds chip on motherboard
established electrical connections
upgrade socks allow upgrading processors
Module A

14. Comparing CPUs Data Bus Width & Word Size
Inside the System Unit
Comparing CPUs
Data Bus Width & Word Size
number of bits in bus determines word size
16-bit CPU works with 16 bit word size
CISC (complex instruction set computer)
many instructions & special-purpose circuits
RISC (reduced instruction set computer)
bare-bones instruction set
less expensive, more efficient
Module A

15. Comparing CPUs Multitasking Pentium MMX Benchmarks Pentium MMX
Inside the System Unit
Comparing CPUs
Multitasking
processor runs more than one program
Pentium MMX
contains 57 sets of multimedia instructions
more quickly run games & multimedia
Benchmarks
provides basis of comparison
Module A
Pentium MMX

16. CPU’s Electronic Scratchpad
Inside the System Unit
Memory:
CPU’s Electronic Scratchpad
Memory Capacities
kilobyte (K or KB),
megabyte (M or MB),
gigabyte (G or GB)
Random-Access Memory (RAM)
store programs & data being used
each memory location has an address
volatile
Cache Memory
allows maximum speed
Module A

17. Inside the System Unit
Random Access Memory
Module A
data
In RAM, each memory location has an address, just like a post office box.

18. Memory Read-Only Memory (ROM) CMOS non-volatile ROM BIOS, flash BIOS
Inside the System Unit
Memory
Read-Only Memory (ROM)
non-volatile
ROM BIOS, flash BIOS
CMOS
used to store startup configuration options
each memory location has an address
volatile
Module A

19. Buses: Freeways for Data
Inside the System Unit
Buses:
Freeways for Data
Circuits that carry data from one component to another are called busses. The wider the bus, the more quickly the data can flow
Module A

20. Inside the System Unit
Plug and Play
Module A
Microsoft and Intel created the Plug and Play (PnP) standard. This standard requires special chips on the motherboard, compatible hardware that is expressly compatible with the Plug and Play standard, and a system BIOS that supports Plug and Play.

21. Data Storage Storage Concepts: The Basics
Disks and Disk Drives: Putting a Spin on it
Magnetic Tape: Still Useful
Optical Storage Media: Seeing the Light
Storing Data in Files
File Systems in Business: Minding the Store
Module B

22. Storage Concepts: The Basics Memory versus Storage B Data Storage
Module B
Memory versus Storage

23. Storage Devices Sequential Random Access
Data Storage
Sequential
go through fixed sequence to get data
example: tape backup unit
Random Access
can go directly to requested data
faster, more expensive
example: disk drive
Module B

24. Before a disk can be used for storage, it must be formatted
Disks & Disk Drives:
Putting a Spin on it
Data Storage
sectors
Before a disk can be used for storage, it must be formatted
Module B
cluster
tracks

25. Floppy Disks A 3 1/2 inch disk B Data Storage write protection tab
plastic casing
liner
disk
Module
sector hole B
spindle hole
read/write opening
sliding metal shutter
A 3 1/2 inch disk