Chapter 3. Computer Hardware. II. A Brief History of Computer Hardware . Without computers many technological achievements would not have been possible: Counting with fingers/toes Blaise Pascal, 1642 – invented the first mechanical adding machine. A Brief History of Computer Hardware .
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Without computers many technological achievements would not have been possible:
Counting with fingers/toes
Blaise Pascal, 1642 – invented the first mechanical adding machine
Herman Hollerith – Hollerith’s Punch Card system to record census data in late 1880’s; 1911 – merged with competitor to form IBM
ENIAC (Electronic Numerical Integrator and Calculator), 1946 – the world’s first electronic digital computer
1950’s – Transistors were invented and replaced tubes
1958 – Integrated Circuit (“chip”) was invented
1970’s – 1980’s
Further miniaturization of circuits
Apple Computer and IBM PC
Computers come in a variety of sizes, shapes, and computing capabilities –
Midrange (obsolete due to powerful microcomputers)
The most important category for businesses and consumers, exceeds the power of many mainframes
Workstations – support mathematical and graphical demands
Network Servers – support telecommunications and resource sharing
Computer Terminals – any device that allows access to a computer
Network Computers – designed specifically for use with networks and the Internet; low TCO (total cost of ownership)
Information Appliances – Web-enabled devices for accessing information from anywhere – cell phones, PDAs, handheld PCs
Why laptops instead of desktops?
Why would a change in OS be disruptive?
What are the strengths vs. risks of cabled vs. wireless PCs?
Midrange Systems – popular as Network Servers; disappearing due to microcomputers
Mainframe Systems – large, fast, and powerful, used for high transaction processing and complex computations; used by corporations and government agencies
Supercomputers – extremely powerful, extremely high speeds and massive numeric computations
The Next Wave of Computing – minisupercomputers; connecting all the power of unused desktops in an organization
Distributed (Grid) Computing – parallel computing over a network
Advantages – purchase nodes as a commodity, economies of scale
Disadvantages – untrustworthy calculations, lack of centralized control
Moore’s Law 1965 – the number of transistors on a chip will double every 18-24 months – essentially, the power or speed of a computer will double every 18-24 months
The Price would halve in that same time, which has also proven to be true
Recent statistics indicate this time has decreased to 12 months
Computer Peripherals: Input, Output, and Storage Technologies
Peripheral - a generic name for all input, output, and secondary storage devices not part of the CPU (basically, what is connected to the outside of the computer)
Input Devices – keyboards, mice, light pens, trackballs, touch screens
Speech Recognition Systems – understands spoken commands/words
Discrete Speech Recognition – speak each word separately
Continuous Speech Recognition – recognizes conversationally-paced speech
Speaker-Independent Voice Recognition – understands speech from a voice it has never heard before
Optical Scanning – converts text or graphics to digital input for direct entry of source documents
Other Input Technologies
Magnetic Stripe – on credit cards
Smart Cards – contain an embedded chip
Magnetic Ink Character Recognition (MICR) – used in banking industry
What does federal Check 21 Act allow?
What is the concern of consumers remotely depositing checks?
What basic security is provided?
What limits/restrictions are placed on the consumers?
Direct and Sequential Access
Direct Access and Random Access are the same concept; locate an address on the storage device and go directly to that location for data access
Sequential Access – All tape devices are accessed serially – device must be read one record at a time from the data until the desired data is found
RAID (Redundant Arrays of Independent Disks) Storage – interconnected groups of hard drives - fast speeds and fault tolerant (redundant backups)
RAM (Random Access Memory) – volatile, may be read and over-written
ROM (Read Only Memory) – non-volatile, may be read but not over-written or erased; PROM and EPROM may be reprogrammed
Flash (Jump) Drives – solid-state memory
Computer Storage Fundamentals
Binary Representation – Two-state, on/off, +/-, 0/1
Bit – Binary digit, 0/1
Byte – Grouping of bits (typically 8 bits/byte), represents a single character
ASCII – formalized code determining what byte values represent which character
Storage capacities – kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB)
Magnetic Tape – slow speeds, but inexpensive for large amounts of backups
Optical Disks – CD-ROM, CD-R, DVD-R (cannot be erased or re-written); CD-RW, DVD-RW (may be erased or re-written)
RFID – for tagging and identifying mobile objects (store merchandise, postal objects, sometimes living organisms); provides information to a reader when requested
Passive – no power source, derives power from the reader signal
Active – self-powered, do not need to be close to the reader
RFID Privacy Issues – may be used as spychips; gathers sensitive information about an individual without consent