The KDS5000 Apple ][ operating system

More about The KDS5000 Apple ][ operating system

Continuing our Apple ][ blog (see previous two pictures), we now take a look at the OS which I wrote for the KDS5000 Kitchen Design System in the early 1980's. Basically, during the development of KDS5000, I found that Apple DOS 3.3 was far too slow for a professional CAD graphics system, mainly because it stored numeric data as Applesoft Basic strings rather than raw integer bytes or words; and also because it interfaced with Applesoft Basic by means of the PRINT statement (as if DOS was pretending to be a paper-tape reader rather than a floppy disk manager).
So, using the Applesoft "&" breakout hook, I wrote a more optimised "command processor", and custom DOS, residing in the "language card", as follows :

&GET "filename", volumenumber -- Open a file
&END volumenumber -- Close a file
X = USR(bytes, volumenumber) -- Read a number of successive bytes, returning the integer value
&STORE value, volumenumber -- Write a string or integer value at the current position on volumenumber
&RUN "progname", volumename -- Run an Applesoft or Assembler program
&PRINT x, y, length, value -- Print value in field length at screen position x, y
&INPUT x, y, type, value -- Input value of type type from the keyboard, at screen position x, y

Here "volumenumber" selects which floppy disk was referenced; Apple DOS gave each formatted floppy a volume number (defaulting to 254), typically we used volumenumber 001 for the program disk, and 002 for the catalogue (data) disk, with 009 as a user save disk. Any volume could be in either drive, the OS prompting the user to "Please Insert Disk NNN" in any drive as appropriate.
KDS5000 also used a custom "Program Protection Card" (inspired by the accounting software "TABS") in slot 7 (the normal disk controller being in slot 6), which contained a custom bootstrap in a 2716 EPROM, to help prevent software piracy.
The KDS5000 custom OS inspired the later Atari 800XL version used in Wanderland; and also the current ::SHE+ILA:: homebrew OS :)