🚀 go-pugleaf

c2a192@ugrad.cs.ubc.ca (Kazimir Kylheku) writes:
>In article <DDt701.DC3@hr.ns.nl>, Illya Vaes  <ivaes@hr.ns.nl> wrote:
>>Look at it this way: on the *same* PC, with the *same* adapters, OS/2, NT, SCO
>>Unix, Linux etc. all are able to address all available RAM. Only DOS can't.
>>Now ask yourself again: is it the hardware (specification) or the software?
>But DOS was developed for machines that could only address 1MB.  That
>DOS wasn't made portable/scalable to a 32 bit architecture is a software
>problem, sure. DOS's system call interfaces are over-specified, in that
>they dicate low-level assembly language details, such as what registers
>pointers are passed in.
[ SNIP ]

I wasn't saying anything about memory *over* 1MB. The whole kludge of UMBs
would not have had to come in existence had DOS been designed to not look only
upto the first adapter, but also beyond. What largest address its internal
structures allow are irrelevant to this.

>Other systems have migrated smoothly from 16 to 32 bit. XINU was developed
>on an 16-bit DEC LSI-11 microcomputer, yet runs on Sun3's and 386 machines
>with few modifications, involving the context switching assembly code,
>startup code and device drivers. That's because all of its kernel interfaces
>are specified as abstracted C calls. You couldn't write code to poke around
>in XINU's internal data structures, since these could easily be re-shuffled
>around when new variables and code is introduced to the kernel.

DOS extenders are 32bit, yet offer an interrupt-based interface (otherwise they
would not be DOS extenders, because they have to use the DOS ints).
-- 
Illya Vaes  (ivaes@hr.ns.nl)
Holland Railconsult BV, Signalling CAD
Postbus 2855, 3500 GW Utrecht
Tel +31.30.358586, Fax 357208           "Do...or do not, there is no try" - Yoda