Hi Eric,
Hi, I want to make TUNS turn on automatically in some cases.
The purpose of the TUNS option is to allocate stacks in low
DOS RAM because, for unknown reason, SCSI BIOSes freak out
(timeouts...) if you call some functions with the stack being
located in an UMB.
Interesting. When I was creating a build of FreeDOS I was very worried
when I read the LBACACHE readme file, especially when it started talking
about data corruption with SCSI drives, so I made sure I used the TUNS
switch. Thing is, LBACACHE is so much smaller than SMARTDRV that it
didn't worry me that it used a few K of lower memory.
In other words: If you 1. have a SCSI disk and 2. want
to LOADHIGH LBACACHE on your system then you 3. have to
use the LBACACHE TUNS option - otherwise disk detection
will likely fail with a timeout.
As I understand it, there's at least two ways of seeing the SCSI disks,
a) the BIOS, b) through a vendor supplied driver. Sometimes the BIOS
gives misleading mapping with very big drives, but on other systems it
seems to work properly. There's also INT13 option in many SCSI BIOS's.
My QUESTION: Do similar things happen with S-ATA or RAID
(or S-ATA RAID) systems as well, is TUNS option needed
on such systems? If so, how do I detect the presence of
S-ATA or RAID?
Again, it may depend on the system and the BIOS. For example the latest
Dell systems (Intel chipsets) will offer both SATA and SCSI drives to
the o/s as if they're IDE drives! In other words, you're seeing the
drives via the BIOS instead of via the controller. On many new AMD
systems (e.g. ASUS and promise) you don't get the BIOS support, so some
kind of driver would be needed, even for SATA.
I wish I knew more about how it all works:(
In the world of Windows, the Dell/Intel solution is very handy because
you can build PCs and servers _without_ worrying about the convoluted
text mode SCSI driver install process. Once Windows is installed, the
PnP driver takes over, and you don't have to worry about it anymore.
The whole idea of hardware RAID, is that you don't need to know if it's
there or not, it's supposed to be abstracted. The controller BIOS (or
vendor driver) presents the containers to the o/s as "physical or
logical drives". The o/s should not need to know (or care) what's going
on behind the scenes, unless you're writing a DOS management agent
(unlikely).
--
Gerry Hickman (London UK)
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