History of Computing. History of Computing. History of Computing. History of Computing. History of Computing. History of Computing VACUUM TUBES ENIAC

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1 s: Analytical Engine Charles Babbage Dawn of Human Concept of Numbers Abacus 1642: Pascal s Machine 1880: Mechanical Tabulator Herman Hollerith 1674: Leibniz Calculating Machine 1911: Hollerith s machine was a complete success and the company that manufactured Hollerith s machine, in 1911, merged with its main competitor

2 2 1947: ENIAC (Electronic Numerical Integrator and Computer) Vacuum Tubes VACUUM TUBES ENIAC 1947: ENIAC 1950:UNIVAC (Universal Automatic Calculator) 1957: IBM 704 VACUUM TUBES Late 1950 s: Transistor-Based Computers Transistorized computers

3 s: Integrated circuits Silicon Photonics New Technology Jack Kilby of Texas Instruments made this, the first integrated circuit, in At virtually the same time Robert Noyce also developed an integrated circuit. Courtesy: Texas Instruments 1970 s: extreme miniaturization Computer System usually a special subsystem of an organization s overall information system 1975: First microcomputer (First PC) 1979: APPLE 1982: IBM PC 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.

4 4 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) Control device gets instructions from memory and interprets them Output devices convert machine (electronic) information into human-intelligible form video displays, printers 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.

5 5 Schematic of a Computer Input Devices Communications devices Processing Device CU ALU registers and buffers Primary Storage (Memory) Output Devices Machine Cycle: The execution of a single instruction. Measured in 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 Instruction: CU fetches an instruction from primary memory and decides what actions need to be taken. 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). How fast is a nanosecond? One billionth of a second Instruction Phase Execution Phase Processing Device CU ALU 2) Decode 3) Execute 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

6 6 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 (200 KHz) (5 MHz) (8 MHz) (10 MHz) (12 MHz) (DX, SL, SX) 1985 (16 MHz up to 33 MHz) (SL, SX) 1989 (25 MHz up to 50 MHz) PENTIUM 1994 (typically MHz) PENTIUM PRO 1995 PENTIUM II 1997 (typically MHz) PENTIUM III 2001 (typically MHz) PENTIUM III-M 2001 (833 MHz 1.3 GHz) PENTIUM IV 2003 (typically 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) Typical PC processors today operate in the 1 to 4 GHz clock speed* Data Hierarchy (cont.) Byte: made up usually of 8 bits a character smallest unit that can be located and moved about in the computer

7 7 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 0 = = = = = = = = = = * = = = / = = = Binary Code - Why is a byte = 8 bits? Capacity - measured in bytes Kilobytes: 1,000 bytes Megabytes: 1,000,000 bytes Gigabytes: 1,000,000,000 bytes Terabytes: 1,000,000,000,000 bytes How do we know which combination of 0 s and 1 s is each letter? EBCDIC ASCII Storage Capacities Primary memory for a PC Typically from 1 Gb to 8 Gb Secondary storage for a PC Typically from 250 Gb to 1 Tb

8 8 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 Digital Images For internet webpage purposes we need 400 X 625 pixels or 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 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 File Format 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.

9 9 Computer System Classifications Microcomputers (PC s) Midrange Systems Peripherals - terminals Dumb terminals - no processing capabilities terminals on a network Intelligent terminals - have processing capabilities 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 Supercomputer Peripherals - pointing devices allow end users to issue commands or make choices by moving a cursor on the display screen 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