From: eric@tantalus.nrl.navy.mil (Eric Youngdale) Subject: Re: Linux 1.0 on CD-ROM? Date: Mon, 1 Mar 1993 01:27:29 GMT
In article <C35C0x.EE@boulder.parcplace.com> imp@boulder.parcplace.com (Warner Losh) writes:
>In article <1993Feb27.014800.21230@netcom.com> yci@netcom.com
>(Yggdrasil Computing) writes:
>>MSCDEX is no different, by the way. It's just
>>that every CD-ROM drive under the sun comes with a floppy disk
>>containing the appropriate MSCDEX drivers and none of them come
>>with Linux drivers.
>
>Has any thought been given to providing wrappers for these driver (or
>even other MS-DOS drivers). Seems like it would save an aweful lot or
>reinvention of the wheel. The kernel could trap all hardware access
>and do it on behalf of the driver, for example. Timing might be a
>problem, so I'm not sure how feasible this idea is.
Unfortunately this will not work because the linux kernel runs in 386
protected mode, and all of the mscdex drivers are all written in 8086 mode. It
would be quite difficult to make any use of the 8086 drivers with the kernel
without resorting to a subprocess running in vm86 mode (as part of the kernel!)
Also, some 8086 device drivers will use polling loops to wait for certain
conditions to become true, and this sort of thing can kill the response time in
a multitasking OS like linux.
-Eric
--
"When Grigor Samsa woke up one morning from unsettling dreams, he
found himself changed in his bed into a monstrous vermin."
-F. Kafka