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DOS only supports two kinds of device drivers: character devices and block devices. It does not have any kind of support for custom file system device drivers,
by bonzini 2y ago
DOS only supports two kinds of device drivers: character devices and block devices. It does not have any kind of support for custom file system device drivers, as block device drivers will only use FAT. So in order to support ISO9660, sectors that aren't 512 bytes, device sizes larger than 32MB (65536 * 512), the device driver (for example ATAPI.SYS) is actually a dummy character device and MSCDEX talks to it to expose the filesystem as a network drive.
- userbinator 2y agoAlternatively, the abstraction of a network drive just happens to be the right one for local filesystem drivers too. There's some more interesting details on the redirector API development here: http://www.os2museum.com/wp/redirectors-and-dos-3-0/ http://www.os2museum.com/wp/redirectors-and-dos-3-0/
- lproven 2y ago> It does not have any kind of support for custom file system device drivers This was true of MS-DOS 1.x and 2.x but not subsequently. The IFS layer was added in MS-DOS 3.1: http://www.bitsavers.org/pdf/microsoft/_MSDOS_releases.txt http://www.bitsavers.org/pdf/microsoft/_MSDOS_releases.txt Although Wikipedia claims MS-DOS 4: https://en.wikipedia.org/wiki/Installable_File_System https://en.wikipedia.org/wiki/Installable_File_System
- trollbridge 2y agoDOS 3.0 had the first “network redirector” support, which was also very buggy. It was rewritten for 3.1 (in an incompatible way) and that has been the standard since. 4.0 tried having a generic IFS which never caught on. Network clients preferred the old interface, and 4.0 was unpopular as it chewed up RAM compared to 3.30. 5.0 reverted to doing network redirectors exactly like 3.30 did.