Messages in this thread | | | Subject | Re: Getting IOCTL's into VFS File System Drivers | Date | Sun, 14 Nov 1999 18:36:08 -0500 | From | "Brandon S. Allbery KF8NH" <> |
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In message <7Ss55F9mw-B@khms.westfalen.de>, Kai Henningsen writes: +----- | That was true since 2.x, actually, and what they mutilated was Xenix. It | was officially called "Xenix compatibility". | | There is a persistent rumour that the "\" thing was because one of the | developers simply got things wrong by accident. +--->8
But wrong. The ITT XTRA MS-DOS 2.11 Reference had a chapter on Xenix compatibility which explained this stuff in detail; I've never seen it in other DOS manuals.
CP/M, and therefore DOS 1.x, used / to signal parameters --- and the CLI knew about this, such that "FOO/X" would be parsed as a command "FOO" with an argument "/X". To maintain compatibility with DOS 1.x while providing an upgrade path to Xenix compatibility, the SWITCHAR could be set via a DOS call or CONFIG.SYS; if set to anything but "/", "Xenix-like" command parsing was used and DOS commands could be invoked with switches preceded by the specified SWITCHAR; 3rd party DOS programs were supposed to use another DOS call to get the SWITCHAR and use it appropriately. ("Xenix-like command parsing" meaning that "FOO-X" was not treated as command "FOO" with switch "-X" if the SWITCHAR was "-".) There was also AVAILDEV which, if set to NO, disabled "bare" device references such as "CON", and you had to use "\DEV\CON" or "/DEV/CON" instead; all the standard DOS 2.11 programs used the \DEV prefix internally so they would work with AVAILDEV=NO, and again 3rd party programs were supposed to query AVAILDEV and behave appropriately.
That chapter also stated that DOS 3.x would default to a SWITCHAR of "-" and would add limited multitasking features, and that DOS would gradually be migrated to full Xenix compatibility, followed by its being fully replaced by Xenix (!). I sometimes wonder what the computing world would be like if Microsoft had actually done this....
-- brandon s. allbery os/2,linux,solaris,perl allbery@kf8nh.apk.net system administrator kthkrb,heimdal,gnome,rt allbery@ece.cmu.edu carnegie mellon / electrical and computer engineering kf8nh We are Linux. Resistance is an indication that you missed the point.
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