From: samiam@netcom.com (Scott Moore)
Subject: Re: Why not standard VESA
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Sat, 19 Dec 1992 07:00:20 GMT

bert.tyler@satalink.com (Bert Tyler) writes:

>Forgive me for responding to a message here that really has little to
>do with OS/2, but as a person who occasionally writes VESA TSRs for
>IBM, I just couldn't let this one go by without a response...

Teed you off eh ? I'll have to point by point this one as well !

>Useless?  You have the "right" to make any claim you want, but this
>one is way off the mark.  Virtually every SuperVGA adapter sold today
>comes with VESA either on the BIOS or as a TSR.  IBM ships PS/2s with
>SuperVGA adapters(*) with MS-DOS SuperVGA modes accessible *only* via a
>VESA TSR (the ValuePoints ship with video adapters accessible via both
>VESA and chipset-specific methods.)  Many SuperVGA MS-DOS apps
>(Links386 Pro is an example, Microsoft C 7.0's graphics libraries are
>another) support SuperVGA *only* for VESA-compliant adapters.  Others
>check for VESA-compliance first, and chipset-specific implementations
>afterwards (the problem with chipset-specific implementations is that
>they tend to work with this week's chipsets, but not with the ones that
>get released next week).  Hardly a textbook case of the term "useless".

Yes, adapter support of the VESA standard is basically universal at this point.
Just as univeral is the software writer's avoidance of it. Many cards also
come with a TSR that supports the "8514" standard, which if you remeber was the
all software interface to the 8514 board. Anyone out there using that thing ?
The important programs have virtually bypassed VESA, such as AUTOCAD and 
windows itself.

>(*) The PS/2 model 25SX, 35, 40, 56, ThinkPad 700C and others, using
>the PS/2 25SX VESA driver (available in Compuserve's IBMPRO forum in
>Library 12 (VESA), filename IBMVES.ZIP).  There's also a freeware VESA
>TSR for the XGA adapter (same Compuserve library, filename XGAVES.ZIP).
>I have seen nothing indicating that IBM's commitment to the VESA standard
>is dying off.

Since IBM claims to be commited to OS/2, and os/2 has nothing to do with VESA,
I have to wonder about that. But I don't remeber saying anything about IBM.

>Maybe you meant to say "Useless in terms of GUIS like OS/2 when those
>GUIs aren't running DOS sessions".  That I would agree with at the moment.

>SM>    [discussing bank-switching:]
>SM>      Now, I could stop right there, and any programmer worth his salt
>SM>will tell you that a high speed driver does NOT stop to make an OS call
>SM>whenever a change of vga memory location is required. I believe that
>SM>this fact alone has kept the VESA standard from spreading even in DOS mode

>See above.  Under MS-DOS, VESA bank-switching is just as fast as
>chipset-specific bank-switching - in fact, the DOS App just makes a
>far call to what is, in effect, the VESA driver's implementation of
>a chipset-specific bank-switching routine.  (There's also a VESA BIOS
>call supporting bank-switching, but any DOS programmer concerned about
>speed and "worth his salt" avoids that overhead and uses the direct call.)

And there is the core of the matter. That direct call is useless with anything
but a true blue DOS app. In my 32 bit adapter/extender days (before os/2),
I was able to call all the VESA functions but that one. That, plus the
requirement to pass the driver an address to a parameter buffer (which any
junior os textbook will tell you is trouble) made creating even a SLOW driver
for VESA impossible. I talked at length with VESA about this problem, 
proposing several solutions (such as providing a 32 bit version of the 
direct call), and was basically told that 32 bit programs were not 
representative of the mainstream. VESA is supposed to plan for the future, not
intrench the past.

>SM>(for instance, why is there no windows driver for VESA ? windows is
>SM>perfectly capable of using VESA BIOS calls).

>There is no incentive for a chipset manufacturer to write a Windows
>(or OS/2) VESA driver, as it would work on his competitors' chipsets
>as well.  Not the cleverest marketing move in the world.  A Windows
>(or OS/2) VESA driver *is* technically possible.  Realistically, though,
>the only vendor with any incentive to build one is the vendor selling
>the GUI itself (Microsoft for Windows, IBM for OS/2).  Also, any
>protected-mode GUI using the current real-mode VESA standard would
>suffer performance penalties due to the need to switch to real mode
>to perform any bank-switching (there is a protected-mode VESA standard
>in the works, but we're all talking about the real-mode version that's
>been around for awhile).

Man, you really doged that one. If VESA was so great, microsoft could have
simply output windows with a VESA driver built in, and that would have
been the end of it. They did not because it would have been a DOG.
Do you really think that microsoft would not have avoided the video driver
wars if they could have ? remember that win 3.0 drivers were hard to get
as well.

>OS/2 (and Windows NT as well) has the additional problem that most VESA
>drivers ship today in the form of DOS TSRs, making them unusable for OS/2
>video drivers.  If IBM provided a VESA-based OS/2 video driver and
>Microsoft provided a VESA-based Windows 3.1 driver, IBM would be in the
>embarrassing position of having to explain why their VESA driver didn't
>work on systems which worked with Microsoft's VESA driver.  They would
>have an excellent technical explanation, but it would still not be a good
>image situation - and image is important.

Your ending wrapup ^^^^^^

Mine:

VESA could have avoided all this nonsense by simply standardizing a single
bank selection port, that, duuuuhhhhh, selects which video page is active.
They could have issued that along with the software standard. Yea, the chip
makers would have screamed. But if enough programs come out to that standard,
they would have gotten in line rapidly.
The unfortunate result has been that SVGA goes virtually unsupported in the
DOS enviornment. Please don't send me a list of VESA programs. Instead,go
down to your local software store and look at side panels. Then tell me how
many off the shelf applications support SVGA. Further, of those that do, 
how many list each adapter they support individually ?
Compare this to the virtual market sweep of VGA and I think I am justified in
calling the situation sad (but probably not VESA's fault).

                                                    [sam]
-- 
Scott A. Moore [SAM]  | "Cash is more 
samiam@netcom.com     | important than your 
Santa Cruz, CA USA    | mother"
408-423-1624          | Allan Shugart - CEO Segate Corp.
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