man41 - 11/3/71 NAME SYNOPSIS DESCRIPTION mem - core memory...

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11/3/71 /DEV/MEM (IV) NAME mem -- core memory SYNOPSIS DESCRIPTION mem maps the core memory of the computer into a file. It may be used, for example, to examine, and even to patch the system using the debugger. Mem is a byte—oriented file; its bytes are numbered 0 to 65,535. FILES SEE ALSO DIAGNOSTICS BUGS If a location not corresponding to implemented memory is read or written, the system will incur a bus—error trap and, in panic, will reboot itself. OWNER ken, dmr
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11/3/71 /DEV/PPT (IV) NAME ppt -- punched paper tape SYNO?S IS DESCRIPTION ppt refers to the paper tape reader or punch, depending on whether it is read or written. When is opened for writing, a 100—character leader is punched. Thereafter each byte written is punched on the tape. No editing of the characters is performed. When the file is closed, a 100—character trailer is punched. When ppt is opened for reading, the process waits until tape is placed in the reader and the reader is on—line. Then requests to read cause the characters read to be passed back to the program, again without any editing. This means that several null characters will usually appear at the beginning of the file; they correspond to the tape leader. Likewise several nulls are likely to appear at the end. End—of—file is generated when the tape runs out. Seek calls for this file are meaningless and are effectively ignored (however, the read/write pointers are maintained and an arbitrary sequence of reads or writes intermixed with seeks will give apparently correct results when checked with tell). FILES SEE ALSO lbppt, dbppt, bppt format DIAGNOSTICS BUGS Previously, there were separate special files for ASCII tape (which caused null characters to be suppressed) and binary tape (which used a blocked format with checksums). These notions were conceptually quite attractive, but they were discarded to save space in the system. OWNER ken, dmr
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11/3/71 /DEV/RFO (IV) NAME rf0 -- RF11—RS11 fixed—head disk file SYNOPSIS DESCRIPTION This file refers to the entire RF disk. It may be either read or written, although writing is inherently very dangerous, since a file system resides there. The disk contains 1024 256—word blocks, numbered 0 to 1023. Like the other block—structured devices (tape, RK disk) this file is addressed in blocks, not bytes. This has two consequences: seek calls refer to block numbers, not byte numbers; and sequential reading or writing always advance the read or write pointer by at least one block. Thus successive reads of 10 characters from this file actually read the first 10 characters from successive blocks. FILES
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This note was uploaded on 04/18/2010 for the course ARCH Arch 101 taught by Professor Edwardhoe during the Spring '10 term at 카이스트, 한국과학기술원.

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man41 - 11/3/71 NAME SYNOPSIS DESCRIPTION mem - core memory...

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