Using Information Technology Chapter 4 Hardware--The CPU & Storage.

Using Information Technology

Chapter 4

Hardware--The CPU & Storage

Hardware--The CPU & Storage How to Buy a Multimedia Computer System

4.1 Microchips, Miniaturization, & Mobility

4.2 The System Unit

4.3 Secondary Storage

4.1 Microchips, Miniaturization, & Mobility

From Vacuum Tubes to Transistors to Microchips

Vacuum Tubes – 18,000 in ENIAC in 1946. Failed every 7 minutes, took 15 minutes to replace!

Transistor (1st was 1/100th size of vacuum tube) - a tiny electrically operated switch, or gate, that can alternate between “on” and “off” many millions of times per second

1960 – 1 transistor was ½ centimeter sq.

2003 – 3 million transistors on ½ cent sq.1940s vacuum tube towering

over 1950s transistor

4

CHIP or MICROCHIP

• A tiny piece of silicon (semiconductor) that contains millions of micro-miniature electronic components, mainly transistors. Silicon is found in sand.

• Microprocessor: Miniaturized circuitry of a computer processor – the part that processes, or manipulates data into information

Steps in Manufacture of a Microchip

1. Make large drawing. Reduce drawing hundreds of times to microscopic size.

2 Duplicate reduced photo many times on sheet.

3 Print sheet of multiple copies on a wafer made of silicon, a semiconductor.

4 Print layer after layer above and below original silicon surface.

5 Cut wafer into chips.

6 Mount chip in frame with connective pins extruding.

[Note: THEN transistors were individually formed. Circuits attached w/wire & solder. TODAY integrated circuits & wires are formed together in a single chip.

4.2 The System Unit

The Binary System: Using On/Off Electrical States to Represent Data & Instructions

The binary system has only two digits--0 and 1.

Bit - binary digit

Byte - group of 8 bits used to represent one character, digit, or other value


Kilobyte 1000 bytes

Megabyte 1,000,000 bytes (one million)

Gigabyte 1,000,000,000 bytes (one billion)

Terabyte 1 trillion bytes

Petabyte 1 quadrillion bytes


ASCII (American Standard Code for Information Interchange) - the binary code most widely used with microcomputers

EBCDIC (Extended Binary Coded Decimal Interchange Code) - used with large computers

Unicode - uses two bytes for each character rather than one. Instead of 256 character combinations of ASCII, 65,536 character combinations allow all languages to be represented.

http://www.unicode.org/

The Computer Case: Bays, Buttons & Boards

Bay - a shelf or opening used for the installation of electronic equipment

System unit - houses the motherboard, power supply, and storage devices

Case - empty box with just power supply

Overhead view of system unit

The Motherboard & the Microprocessor Chip

Motherboard - the main circuit board in the system unit

Expansion - increasing a computer’s capabilities by adding hardware

Upgrading - changing to newer, more powerful versions


Two principal architectures or designs of microprocessors:

CISC (Complex Instruction Set Computing) - Supports a large number of instructions at relatively low processing speeds

RISC (Reduced Instruction Set Computing) - Supports a reduced number of instructions in order to obtain faster processing speeds

Two kinds of microprocessors used in most microcomputers today:

Intel-type chips for P/Cs made by Intel, AMD, and others (Pentium. The P4 has 42 million transistors)

Motorola-type chips made by Motorola for Apple Macintosh computers


MICROPROCESSOR – contains a system clock, which controls how fast all the operations within a computer takes place

System clock – uses fixed vibrations from a quartz crystal to deliver a steady stream of digital pulses or “ticks” to the CPU.

Ticks are called cycles

Faster clock speeds result in faster processing and execution of program instructions.

Steps in the machine cycle (Tick) [series of operations performed by control unit to execute a single programmed instruction]:

1. Fetch an instruction

2. Decode the instruction

3. Execute the instruction

4. Store the result Microprocessor speed expressed in Megahertz, a frequency equivalent to 1

million cycles (ticks) per second. (1 GHz - 1 billion cycles per second)

How Processor or CPU works: Control Unit, ALU, & Registers

CPU – Central processing unit (Brain): consists of 2 parts (both contain registers, high speed storage areas).

2 parts are linked by electronic roadways “bus.”

1. Control unit – deciphers each instruction stored in it and carries out. Directs electrical signals bet main memory & ALU & input/output devices.

2. Arithmetic Logic Unit – ALU – performs arithmetic & logic operations (comparisons) & controls speed

How Processor or CPU works: Control Unit, ALU, & Registers

Word size - # of bits a processor may process at one time. 32-bit “word” microprocessor will transfer data w/in each processor chip in 32-bit chunks.

BUS – bits are transmitted within the CPU and between CPU & other components of motherboard.

How Memory Works: RAM, ROM, CMOS, & Flash

Types of memory chips:

1. RAM - Random Access Memory, used to temporarily hold software instructions & data in main memory (volatile)

2. ROM

3. CMOS

4. Flash

4 types of RAM chips:1. DRAM – Dynamic RAM – must be constantly refreshed

2. SDRAM – Synchronous DRAM – Synchronized by system clock, goes faster

3. SRAM – Static RAM – doesn’t need to be refreshed, faster than DRAM



1. RAM

2. ROM - Read-Only Memory, which cannot be written on or erased by the computer user. Contains fixed start-up instructions

3. CMOS

4. Flash



1 RAM 2 ROM 3 CMOS - Complementary metal-oxide semiconductor;

powered by a battery and thus doesn’t lose its contents when the power is off (non volatile)

4 Flash



1 RAM 2 ROM 3 CMOS 4 Flash memory chips – to store program - can be erased and

reprogrammed more than once (non volatile)

How Cache Works: Level 1 (Internal) & Level 2 (External)

Cache - temporary storage for instructions and data that the processor is likely to use frequently, thus speeding up processing

Level 1 (L1) internal cache - built into the microprocessor (8-256 kilobytes – operates fast)

Level 2 (L2) external cache - consists of RAM chips outside microprocessor (64-2MB)

Virtual memory - current operating systems allow for use of free hard-disk space used to extend the capacity of RAM

Ports & Cables

Types of ports (connecting socket or jack on the outside of the system unit into which are plugged different kinds of cables):

1 Serial port - sends bits one at a time, one after another (keyboards, mouse, monitor, modem)

2 Parallel port3 SCSI port4 USB port5 Dedicated port6 Infrared port

Ports & Cables

1 Serial port 2 Parallel port -

transmits 8 bits simultaneously (fast data over short distances – 15 ft) (printers, external zip drive)

3 SCSI port4 USB port5 Dedicated port6 Infrared port

Ports & Cables

1 Serial port 2 Parallel port3 SCSI port - allows

fast data to be transmitted in a “daisy chain” to up to 7 devices

4 USB port5 Dedicated port6 Infrared port

Ports & Cables

1 Serial port 2 Parallel port3 SCSI port 4 USB Port (universal serial bus) - can

theoretically connect up to 127 peripheral devices daisy-chained to one general-purpose port (allows plug & play – so peripheral devices & expansions cards can be automatically configured while they are being installed.

5 Dedicated port6 Infrared port

Ports & Cables

1 Serial port 2 Parallel port3 SCSI port 4 USB5 Dedicated port -

special-purpose ports

6 Infrared port

Dedicated ports: mouse port, telephone jack, modem port, and

keyboard port

Ports & Cables

1 Serial port 2 Parallel port3 SCSI port 4 USB5 Dedicated port - special-

purpose ports6 Infrared port - allows a

computer to make a cableless connection with infrared-capable devices (handheld TV remote)

Expandability: Buses & Cards(Open vs. closed architecture)

Expansion slots- sockets on the motherboard into which you can plug expansion cards

Expansion cards - circuit boards that provide more memory or that control peripheral devices

Expandability: Buses & Cards

ISA bus (industry standard architecture) - for ordinary low-speed uses; the most widely used expansion bus

PCI bus (peripheral component interconnect)- for higher-speed uses; used to connect graphics cards, sound cards, modems, and high-speed network cards

AGP bus (accelerated graphics port) - for even higher speeds and 3D graphics

Note: system bus connects CPU to itself and to main memory

Expandability: Buses & Cards

Graphics cards - for monitors

Sound cards - for speakers and audio output

Modem cards - for remote communication via phone lines

Network interface cards - for remote communication via cable

PC cards - for laptop computers (formally PCMCIA cards)

4.3 Secondary Storage

Floppy disk

a removable flat piece of mylar plastic packaged in a 3.5-inch plastic case

Data & programs are stored on disks coating with magnetic spots following on/off patterns of data representation.

Tracks

sectors

DISK STORAGE

Floppy disk – 1.44 MB (400 typewritten pages)

Zip disks - 100 or 250 Mb

*SuperDisks - 120 Mb

*HiFD disks - 200 Mb

*Drive can also read floppy

Hard Disks

Hard disks - thin but rigid metal platters covered with a substance that allows data to be held in the form of magnetized spots

Read/write head does not touch disk; rides on air cushion

Hard Disks

Head crash - event that happens when the surface of the read/write head or particles on its surface come into contact with the surface of the hard-disk platter, causing the loss of some or all of the data on the disk

Hard DisksNonremovable hard disks - housed in a microcomputer system unit and used to store nearly all programs and most data files

See p. 164

Hard Disks

Removable hard disks - one or two platters enclosed along with read/write heads in a hard plastic case, which is inserted into a microcomputer’s cartridge drive

Bits on disk - dark stripes are 0 bits and bright stripes are

1 bits

Optical Disks: CDs & DVDs

Optical disk - a removable disk on which data is written and read through the use of laser beams


CD-ROM - read only. For pre-recorded text, graphics, and sound

CD-R - for recording on once

CD-RW - for rewriting many times

CD-Rom Drive’s speed denoted as data transfer by X which represents rate of 150 kilobytes per second. (44X = 44x150 kb)


DVD-ROM - for reading only [extremely high capacity (4.7-11.7 gigabytes)

DVD-R - for recording on once

For rewriting many times:

DVD-RWDVD-RAM DVD+RW

http://www.netflix.com/

Magnetic Tape (up to 66 gigabytes)

Magnetic tape - thin plastic tape coated with a substance that can be magnetized (for 1s) or left non-magnetized (for 0s)

Tape cartridges - modules resembling audio cassettes that contain tape in rectangular, plastic housings

Smart Cards

Smart card (holds up to 250 pgs of data)

Looks like a credit card but contains a microprocessor embedded in the card (e.g., telephone debit card)

Optical card (holds up to 2000 pgs of data) Plastic, laser-recordable, wallet-type card used with an optical-card reader

[Note: conventional credit card strip holds ½ page of data]

Smart card in use

Flash Memory Cards

Flash memory card – circuitry on credit-card-size PC card that can be inserted into slots connecting to the motherboard

64 MB – projected up to 1 gigabyte

Concept Check

Which binary code is most often used with microcomputers?

ASCII (American Standard Code for Information Interchange)

Concept Check

How many bytes are in a terabyte?

One trillion

Concept Check

Which type of CD can be written to only once?

CD-R

Concept Check

Which binary code can represent all the characters of virtually every language in existence?

UNICODE

Concept Check

Which chip architecture provides faster processing speed--CISC or RISC?

RISC

Concept Check

Which measure of storage represents one billion bytes?

Gigabyte

Concept Check

What are the two parts of the CPU?

Control unit and arithmetic/logic unit (ALU)

Concept Check

What is the term for increasing a computer’s capabilities by adding hardware to perform tasks beyond the scope of the basic system?

Expansion

Concept Check

What is a gigahertz?

A measure of processing speed representing one billion cycles per second

Concept Check

What is the term for the special high-speed memory area on a chip that the CPU can access quickly?

Cache

Concept Check

What element are wafers composed of?

Silicon

Concept Check

What are the four steps of the machine cycle?

1. Fetch an instruction

2. Decode the instruction

3. Execute the instruction

4. Store the result

Using Information Technology Chapter 4 Hardware--The CPU & Storage.

Documents

binary system

cpu storage slide

information slide

second slide

system unit expansion

value slide

control unit

secondary storage slide