ISIS (operating system)
||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (August 2014)|
|Written in||Assembler, PL/M|
|Source model||Closed source|
|Marketing target||exclusively for Intel Microprocessor Development System|
|Platforms||Intel 8080, Intel 8085|
ISIS is an operating system, created by Intel for their Intel Microprocessor Development System around 1976, and adopted as ISIS-II for systems with floppy drives. Communication with the user is terminal-like. Its user interface is Unix-like, even from the program interface point of view; communication with the kernel is this way (e.g., for file opening, the program sends the name of file and gets back a handle). Each device has a name, which is entered between a pair of colons (:F0: and :F1: are floppies, :LP: is printer, etc.). Each diskette has one directory and no subdirectories. ISIS-II has been distributed as part of the Intel Microprocessor Development System and includes standard operating system commands (copy, delete, dir, rename, format) and debugging software (assembler, linker and debugger for external debugging in developed device). There are two editors, one of which, AEDIT, contains editing macros support. File editing is provided directly on diskette (a .BAK file is always created). The other editor is CREDIT.
For running ISIS-II, at least 32 kilobytes of RAM was demanded (maximum was 64 kilobytes minus the boot system size). Floppy disk format was 8-inch single-sided, 250 kB single-sided, single-density, or 500 kB single-sided, double-density; later replaced with 5¼ inch double-sided double-density in a "portable" development system (iPDS-100). Operating system itself was independent of device.