History of Computing • 1800’s: Analytical Engine – Charles Babbage

History of Computing • Dawn of Human Concept of Numbers • Abacus • 1642: Pascal’s Machine

History of Computing • 1674: Leibniz Calculating Machine

History of Computing • 1880: Mechanical Tabulator – Herman Hollerith

History of Computing • 1911: Hollerith’s machine was a complete success and the company that manufactured Hollerith’s machine, in 1911, merged with its main competitor

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History of Computing • 1947: ENIAC (Electronic Numerical Integrator and Computer) • Vacuum Tubes

History of Computing • ENIAC

History of Computing • VACUUM TUBES

History of Computing • 1947: ENIAC • 1950:UNIVAC (Universal Automatic Calculator) • 1957: IBM 704

History of Computing • VACUUM TUBES

History of Computing • Late 1950’s: Transistor-Based Computers • Transistorized computers

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History of Computing • 1960’s: Integrated circuits

New Technology • Silicon Photonics

Jack Kilby of Texas Instruments made this, the first integrated circuit, in 1958. At virtually the same time Robert Noyce also developed an integrated circuit. Courtesy: Texas Instruments

History of Computing • 1970’s: extreme miniaturization

History of Computing • 1975: First microcomputer (First PC) • 1979: APPLE

Computer System • usually a special subsystem of an organization’s overall information system

Hardware • Any machinery (most of which utilizes digital circuitry) that assists in the performance of the input, processing, and output activities of an information system.

• 1982: IBM PC

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Input devices • convert data into machine readable form – eg. keyboard, mouse, scanner

Storage devices • store data & program instructions needed for processing – Primary storage devices - memory (RAM) – Secondary storage devices - hard disk, floppy disks, CD, DVD, jump drives.

Processing devices • CPU (Central Processing Unit)

Output devices • convert machine (electronic) information into human-intelligible form – video displays, printers

Control device • gets instructions from memory and interprets them

Central Processing Unit (CPU)  Control unit: central switchboard or manager  gets instructions from memory (Fetch) and interprets them (Decode)

 Arithmetic logic unit: performs two functions:  Mathematical operations  Logical comparisons of both numbers and strings.

 Registers  are high-speed storage areas used to temporarily hold small units of program instructions and data immediately before, during, and after execution by the CPU.

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Schematic of a Computer

CPU (continued) • Machine Cycle: The execution of a single instruction.

Communications devices

– Measured in

Processing Device CU

Input Devices

ALU

registers and buffers

Output Devices

Primary Storage (Memory)

• • • •

Milliseconds: one thousand of a sec. Microseconds: one millionth of a sec. Nanoseconds: one billionth of a sec. Picoseconds: one trillionth of a sec.

Secondary Storage

Phases

CPU (continued)

• Instruction: – CU fetches an instruction from primary memory and decides what actions need to be taken.

• How fast is a “nanosecond”? • One billionth of a second

• Execution: – The ALU accesses the necessary data from primary memory, places it into the registers, performs the operations (Execute), and returns the result to memory (Store).

Instruction Phase

CPU (continued)

Execution Phase Processing Device CU

ALU 3) Execute

2) Decode 1) Fetch

registers

4) Store

Primary Storage (Memory)

• How fast is a nanosecond? • If a man of average leg span took a step every nanosecond, he would circle the earth about 20 times in one second

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CPU (continued) • Clock Speed: A measure of processing speed. Electronic pulses the CPU produces at a predetermined rate – usually measured in megahertz (millions of cycles per second) or gigahertz (billions of cycles per second) – the higher the clock speed, the faster the machine cycle

Intel Microprocessor Chips               

8080 1974 (200 KHz) 8086 1978 (5 MHz) 8088 1979 (8 MHz) 80186 1982 (10 MHz) 80286 1982 (12 MHz) 80386 (DX, SL, SX) 1985 (16 MHz up to 33 MHz) 80486 (SL, SX) 1989 (25 MHz up to 50 MHz) PENTIUM 1994 (typically 60 – 233 MHz) PENTIUM PRO 1995 PENTIUM II 1997 (typically 233 - 450 MHz) PENTIUM III 2001 (typically 400 - 900 MHz) PENTIUM III-M 2001 (833 MHz – 1.3 GHz) PENTIUM IV 2003 (typically 2.4– 3.5 GHz) OHTERS: PENTIUM 4-M, XEON, Itanium, Dual-Core, Dual-Core 2 Core-Quad, Core-Extreme, Core-i7, Core™ i7 VPro

CPU (clock speed) • • • • •

Hz (1 cycle per second) Kilohertz (KHz) (1000 cycles per second) Megahertz (MHz) (1,000,000 cycles per second) Gigahertz (GHz) (1,000,000,000 cycles per second) Terahertz (THz) (1,000,000,000,000 cycles per second)

Data Hierarchy • Bit: – binary digit – physical representation of data in a computer (letters, numbers and symbols must be represented to the computer as a combination of 0s or 1s: off or on)

CPU (continued)

Data Hierarchy (cont.) • Byte:

• Typical PC processors today operate in the 1 to 4 GHz clock speed*

– made up usually of 8 bits – a character – smallest unit that can be located and moved about in the computer

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Data Hierarchy (cont.) • Field: made up of bytes (name: George) • Record: made up of several fields (name, address, telephone) • File: made up of several records • Application: made up of several files • System: made up of several applications

ASCII • • • • • • • • • •

Binary Code - Why is a byte = 8 bits?

* = 0010 1010 + = 0010 1011 - = 0010 1101 / = 0010 1111 = = 00111101

Capacity - measured in bytes • • • •

How do we know which combination of 0’s and 1’s is each letter?

0 = 0011 0000 1 = 0011 0001 2 = 0011 0010 3 = 0011 0011 4 = 0011 0100 5 = 0011 0101 6 = 0011 0110 7 = 0011 0111 8 = 0011 1000 9 = 0011 1001

• • • • •

Kilobytes: 1,000 bytes Megabytes: 1,000,000 bytes Gigabytes: 1,000,000,000 bytes Terabytes: 1,000,000,000,000 bytes

Storage Capacities • Primary memory for a PC

• EBCDIC

– Typically from 1 Gb to 8 Gb

• Secondary storage for a PC – Typically from 250 Gb to 1 Tb

• ASCII

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Digital Images

Storage Capacity - Old Technology • Floppy disks – 3 1/2” - 720 KB (DD) and 1.44 MB (HD) – 5 1/4” - 360 KB (LD) and 1.2 MB (HD)

• Zip drives (floppy-like technology) – up to 750 MB

• Optical Disks – CD-ROM – typically 600 to 700 Mb (about 400 floppy equivalent) • CD-R (permanently record) • CD-RW (rewritable)

– DVD – typically 4.7 Gb – Double Layer DVD – typically 8.5 Gb

• For internet webpage purposes we need 400 X 625 pixels • or 250 000 pixels • or 250 Kilopixels • or ¼ Megapixels • 2 Megapixel image = 2,000,000 pixels • 3 Megapixel image = 3,000,000 pixels • 8 Megapixel image = 8,000,000 pixels • 14 Megapixel image = 14,000,000 pixels

Storage Capacities – New Technology

File Format

• Optical Disks – Blu ray DVD – 25 Gb up to 50 Gb for dual layer

• USB Flash Drives – typically from 256 Mb to 512 Gb • Memory Cards – typically from 32 Mb to 512 Gb • USB External Hard Drives – from 100 Gb to 12 Tb

• • • •

JPEG or JPG – Joint Photographic Experts Group GIF – Graphics Interchange Format PNG – Portable Network Graphic TIFF – Tagged Image File Format

Digital Images • • • • •

¼ Megapixel image: 50 Kb in JPG format 2 Megapixel image: 250 Kb in JPG format 3 Megapixel image: 650 Kb in JPG format 8 Megapixel image: 2 MB in JPG format 14 Megapixel image: 5 MB in JPG format

Primary Storage • RAM: – Random Access Memory – Where data and program instructions wait to be interpreted. – Volatile Memory

• ROM: – Read Only Memory – Instructions (programs) are burned into a chip and cannot be altered.

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Computer System Classifications • Microcomputers (PC’s)

Peripherals - terminals • Dumb terminals - no processing capabilities – terminals on a network

• Intelligent terminals - have processing capabilities • Midrange Systems

– microprocessor and memory circuits

• Transaction terminals – get data from end users and transfer the data via Telecommunication networks to a computer system for processing – eg. ATM’s

Computer System Classifications (cont.) • Mainframe

Peripherals - pointing devices • allow end users to issue commands or make choices by moving a cursor on the display screen

• Supercomputer

– mouse – trackball – joystick – touch sensitive screens

Peripherals • Input/output equipment and secondary storage devices all controlled by the CPU • Direct input/output devices – Input - keyboard, mouse, pens, touch screens, wands, scanners (OCR), speech recognition. – Output – video monitors, printers, voice response

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