管理信息系統(tǒng)計(jì)算機(jī)硬件軟件-文庫吧在線文庫
【正文】 ICAL STORAGE SECONDARY STORAGE TRACKS START OF TRACKS DIRECTORY ON TRACK 0 SECTOR EACH TRACK HOLDS SAME AMOUNT OF DATA TRACKS AND SECTORS Source: Senn, Information Technology in Business1995 DISK PACK STORAGE ? LARGE SYSTEMS ? RELIABLE STORAGE ? LARGE AMOUNTS OF DATA ? QUICK ACCESS amp。 A building。 efficiency. 3. Telemunication channels amp。 RETRIEVABLE ? TYPICAL: 11 2SIDED DISKS ? CYLINDER: SAME TRACK ALL SURFACES CYLINDER 10: TRACK 10 (TOP AND BOTTOM OF EACH DISK) DISK 1 DISK 2 DISK 3 DISK 4 DISK 5 READ/WRITE HEADS ? STANDARD FOR SEQUENTIAL FILES ? SPOOL OF PLASTIC TAPE COVERED WITH FERROUS OXIDE (2400 feet per spool) ? RECORD GROUPS: BLOCKING FACTOR (., 10 records per block) ? GROUPS SEPARATED BY INTERBLOCK GAP ? RECORDS READ BLOCK AT A TIME * HEADER IBG BLOCK 1 BLOCK 2 BLOCK 3 MAGNETIC TAPE ? ENCLOSED FERROUS OXIDE TAPE ? USED PERIODICALLY TO BACK UP RECORDS ? INEXPENSIVE ? STORED IN SAFE LOCATION ? CAN BE REUSED MAGNETIC CARTRIDGE ? CDROM: 500660 MEGABYTES –LAND: FLAT PARTS OF DISK SURFACE REFLECTS LIGHT –PITS: SMALL SCRATCH ON SURFACE SCATTERS LIGHT ? WORM: WRITE ONCE / READ MANY ? ERASABLE OPTICAL STORAGE (EOS) DISKS * OPTICAL STORAGE MULTIMEDIA WORKSTATION CDROM HEADPHONES STEREO SPEAKERS LEFT, RIGHT, WOOFER SUPER VGA MONITOR VIDEO BOARD + EXTRA MEMORY STEREO SOUND BOARD (32 BIT: WAV, MIDI, CD) AT LEAST 16 MG RAM (32 MG MUCH BETTER) JOYSTICK HARD DRIVE: 1 GIG OR MORE, JAZ DRIVE 通訊網(wǎng)絡(luò)的組成 “ Any one in the world could be your customer。 A manufacturing plant. Pc workstation Workgroup database Shared printer Network Server Shared Hard Disk Unit Gate way to other work WANs Wid
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