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Peripheral Interchange Program
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Peripheral Interchange Program (PIP) was a utility to transfer files on and between devices on Digital Equipment Corporation's computers. It was first implemented on the PDP-6 architecture by Harrison "Dit" Morse early in the 1960s. It was subsequently implemented for DEC's operating systems for PDP-10 and PDP-11 architectures.
was originally named ATLATL, which was an acronym for "Anything, Lord to Anything, Lord." This humorously described both its purpose as a device-independent file copying tool and the difficulties at the time of safely copying files between devices.
The original PIP syntax was
PIP destination?source
as the Flexowriter keyboards of the time, which used ASCII-1963, had the left-arrow symbol in their character set; as other terminals that used later versions of ASCII, lacking the left-arrow, were introduced, PIP allowed the syntax
PIP destination=source
The underscore (_) character, which was in the ASCII position that left-arrow had occupied, was still supported to separate the destination and source specifications.
As late as the mid 1980s, PIP was still in common use on TOPS-10 and TOPS-20 systems.
r Gary Kildall started CP/M, he took the PIP and file concepts as well.
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Encyclopedia
Peripheral Interchange Program (PIP) was a utility to transfer files on and between devices on Digital Equipment Corporation's computers. It was first implemented on the PDP-6 architecture by Harrison "Dit" Morse early in the 1960s. It was subsequently implemented for DEC's operating systems for PDP-10 and PDP-11 architectures.
History
PIP was originally named ATLATL, which was an acronym for "Anything, Lord to Anything, Lord." This humorously described both its purpose as a device-independent file copying tool and the difficulties at the time of safely copying files between devices.
The original PIP syntax was
PIP destination?source
as the Flexowriter keyboards of the time, which used ASCII-1963, had the left-arrow symbol in their character set; as other terminals that used later versions of ASCII, lacking the left-arrow, were introduced, PIP allowed the syntax
PIP destination=source
The underscore (_) character, which was in the ASCII position that left-arrow had occupied, was still supported to separate the destination and source specifications.
As late as the mid 1980s, PIP was still in common use on TOPS-10 and TOPS-20 systems.
PIP in CP/M
After Gary Kildall started CP/M, he took the PIP and file concepts as well. Besides accessing files on a floppy disk, PIP in CP/M could also transfer data to and from the following "special files":
- CON: — console (input and output)
- AUX: — an auxiliary device. In CP/M 1 and 2, PIP used PUN: (paper tape punch) and RDR: (paper tape reader) instead of AUX:.
- LST: — list output device, usually the printer
- PRN: — as LST:, but lines were numbered, tabs expanded and form feeds added every 60 lines.
- NUL: — null device, akin to /dev/null
- EOF: — input device that produces end-of-file characters, ASCII 0x1A
- INP: — custom input device, by default the same as EOF:.
- OUT: — custom output device, by default the same as NUL:.
These are not true device files however, because their handling is limited to PIP. The two custom devices were implemented by calls to fixed locations at the start of the PIP program; the intention was that the user, or the OEM, could patch these locations to add their own input or output device. 246 bytes of free space were left in the program for this purpose.
In addition to the usual PIP destination=source syntax, PIP under CP/M still allowed the old PIP destination_source form. This behaviour was not documented, and CP/M generally did not have a standard for which characters could appear in file names; therefore other programs could and did create filenames containing underscore characters, which PIP could not handle.
See also
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