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Fundamentals of Computer Systems and Data Storage. Todd S. Bacastow Assistant Director, EMS Environment Institute. Computer Fundamentals. Hardware = physical components of a computer Software = non-physical components of a computer
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Fundamentals of Computer SystemsandData Storage Todd S. Bacastow Assistant Director, EMS Environment Institute Todd S. Bacastow
Computer Fundamentals • Hardware = physical components of a computer • Software = non-physical components of a computer • Data = pieces of information that are operated on by programs Todd S. Bacastow
Computer displays • Raster: pixel oriented, with all text and graphics made up of individual dots. Almost all common computer devices are raster, including monitors, laser printers, ink jet printers, and dot matrix printers. • Vector: text and graphics are composed on line segments. The only common vector devices are pen plotters, which physically move a pen across the paper. Todd S. Bacastow
CRT (cathode ray tube) Todd S. Bacastow
Standard Resolution Number of pixels Recommended screen size VGA 640 x 480 307,200 14" SVGA 800 x 600 480,000 15", 17" SVGA 1024 x 768 786,432 17", 19" XGA 1152 x 864 995,328 17", 19", 21" Vesa 1280 1280 x 1024 1,310,720 19", 21" Vesa 1600 1600 x 1200 1,920,000 21" Todd S. Bacastow
Primary Memory Todd S. Bacastow
The physical drive principle Disk types Magnetic Floppy disks Hard disk Syquest disks Zip drive LS-120 disks Optic CD-ROM DVD Magneto optic High end drives Secondary Memory Todd S. Bacastow
Disk Drives Todd S. Bacastow
Data storage • Computers store all data as a series of ones and zeros • integers = the counting numbers • Can be stored exactly • real or floating point numbers • stores reals as an exponent and mantissa, which allows precision to a given number of decimal places depending on the number of bytes used • Real arithmetic requires much more computer processing power than integer arithmetic Todd S. Bacastow
Number storage methods • Binary = number system that uses only 1 and 0 (1 bit) • Hexadecimal = number system that uses 16 digits, 0-9 and a-f (4 bits) • ASCII = American Standard Code for the Interchange of Information. A code that uses 128 values to transfer text data between computers. (7 bits per character) Todd S. Bacastow
Number storage • Binary • 8 bits (1 byte) provides 256 combinations • 16 bits (2 bytes) provides 65536 combinations Todd S. Bacastow
Numbers, as known in the decimal-system Same numbers in binary system 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 Binary System Todd S. Bacastow
Real Numbers • 11000011100101100000000000000000 • negative because the sign bit is 1 • exponent of 8 (because the exponent bits, 10000111, form the binary numeral for 135, and therefore represent the exponent 8 when the bias of 127 is removed) • mantissa is expressed by the binary numeral 1.00101100000000000000000, where the initial 1 is the hidden bit and the remaining digits are taken from the right end of the word • This last binary numeral expresses the number 75/64 (one, plus no halves, plus no quarters, plus one eighth, plus no sixteenths, plus one thirty-second, plus one sixty-fourth). • the complete number is -(75/64) x 2^8, which is -300.0 Todd S. Bacastow
Byte order • LSB = least significant byte first • Little-endian • MSB = most significant byte first • Big-endian Todd S. Bacastow
Data Storage Sizes • Bit: the smallest element used by a computer, a 0/1. • Byte: eight bits. • Kilobyte: 210 (1024) • Megabyte: 220 (10242=1,048,576 ) • Gigabyte: 230 (10243=1,073,741,824) • Terabyte: 240 (10244=1,099,511,627,776) Todd S. Bacastow
Storage media • Floppy disks: store 1.44 MB • Zip disks: original version stores 100 MB • JAZZ disks: stores 1 GB • CD-ROM: store 650 MB • CD-R: CD-Recordable; these can be “burned” once • CD-RW:CD-Rewrite; these can be written over • DVD: store the equivalent of 5-6 CD-ROMs Todd S. Bacastow
Storage media Todd S. Bacastow
Communications • Parallel port: used for the printer, external ZIP drives, scanners, and cameras. 25 pin connector • Serial port: used for external modems, mice, and connecting instruments. 9 pin connector • USB: Universal Serial Bus: a faster and better connection that lets you change components on the fly. • SCSI: (Small Computer System Interface): less common standard for computers, looks like large printer connectors. Todd S. Bacastow
Software • Operating system: the computer code that lies between the hardware and the applications programs a user wants to run. Examples include Unix, Linux, Windows 98 or NT. • Application program: something a user wants to run, such as a word processor, spreadsheet, or web browser. • Language: a tool for programmers, which has syntax for telling the computer what to do. Todd S. Bacastow
Booting Todd S. Bacastow
Utility Programs with Windows • Notepad: reads small ASCII files. If you try to read too large a file, it will use WordPad. • WordPad: reads ASCII files, and Microsoft Word format. Todd S. Bacastow