NCR PC4i Owner's Manual

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Contents

NCR PC4i Owner's Manual Manual pdf 29 page image

HISTORICAL DATANCR ASCII CODE CHART\ » 4 B» 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 TOT 1 1100 1101 1110 1111m l » s \ 0 1 2 3 4 s • 7 8 8 A B c D E F0 0 0 0 0 N U L SOH STX ETX EOT ENO ACK BEL BS MT LF V T FF CR SO SiOOOl 1 DLE D O DC2 DC3 DC4 N A K SYN ETB CAN EM SUB ESC FS GS RS US0010 1 - ft S % & ■ 1 1 • . - /0011 3 0 1 2 3 4 5 6 7 a 9 < > tD100 4 e A 6 C D E F G H 1 J K L M N o0101 5 P 0 R s T U V w X Y z t \ 1 A0110 6 * a b c d e » 9 h . 1 h 1 m » o0111 7 P q . t , u Wl . V / 1 ; 1 — DELFigure 1-4 ASCII Code ChartRecording Data in Internal MemoryThe ability of hardware designers to package more and more memoryinto smaller and smaller spaces has been a major factor in theredaction in size from the days when Univac I, as the state-of-the-art,required a bedroom-sized memory and processor enclosure to hold amemory of 10,000 12-bit words.In the Univac I, bits were stored as electrical pulses recirculatedthrough tanks of liquid mercury. Soon that and other early storagetechniques were superceded by the use of magnetic core memories.Each ferrite core, shaped like a tiny donut, represented one bit ofinformation. From 16K to 64K bytes of data could be stored in a corearray about the size of a suitcase. Core memories, in turn, have beenfollowed by metal oxide semiconductor (MOS) memories. Integratedcircuits using MOS technology make possible the storage of 64K ormore bits on a single, small chip.Your NCR Personal Computer, an example of today’s state-of-the-art, can have up to 640K 8-bit bytes within its relatively small cabinetalong with the disk drives, main processor, other circuit boards, andthe power supply.Recording Data in External MemoryFixed DisksThe fixed disk available on the NCR Personal Computer can storeover 20,000,000 bytes (20 megabytes, or 20 MB). Since the maximumcapacity of each diskette used in your flexible disk drive(s) is 368,640bytes (360 KB), you can see that with one fixed disk drive you have theOWNER'S MANUAL 1-21