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Super VGA with the Tandy 1000 RLX

Cloudschatze

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Managed to get another RLX annoyance crossed off my list...

Both the NCR 77C20 and Acumos AVGA1 video chipsets of the Tandy 1000 RLX-A and RLX-B, respectively, support the lesser Super VGA resolution of 800x600, with 16-colors, at 57Hz. Disappointingly, neither system variant includes video BIOS support for this mode, seemingly precluding its use in Windows 3.0/3.1 and GeoWorks/NewDeal Office, where graphical corruption and/or error messages result if attempted.

As it turns-out, there's a pretty simple solution; albeit, one that costs 28KB of conventional memory. Tucked away in a few driver packages for the AVGA1 chipset is a RAM-based BIOS TSR, "RAMBIOS.COM," that includes the SVGA extension support.
Surprisingly, this RAM-based video BIOS works with either RLX video chipset, as do the related driver selections that follow.

With the RAM-based video BIOS loaded, use of Windows' standard Super VGA driver becomes possible (SUPERVGA.DRV), as does the "AVGA-specific" 800x600, 16-color driver (VGA1800.DRV/AVGA816.DRV). I'm using the latter here:

RLX_WIN1.JPG


Pardon the photograph, but there simply isn't enough system memory to get a screen capture, even sans any loaded programs. Thanks, Microsoft!


With GeoWorks/NewDeal Office, the "VESA Compatible Super VGA: 800x600 16-color" display option can be selected and used.

RLX_NDO1.PNG


RLX_NDO2.PNG


Concurrent e-mail, web-browsing, and IRC, and I'm still able to get screen dumps. Thanks, GeoWorks!


In case any of this is helpful, here is an archive that includes both the aforementioned RAMBIOS.COM utility, and the VGA1800.DRV driver that can be used in both Windows 3.0 and 3.1:
http://www.symphoniae.com/misc/VC/500203.zip
 
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Eudimorphodon

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Both the NCR 77C20 and Acumos AVGA1 video chipsets of the Tandy 1000 RLX-A and RLX-B, respectively, support the lesser Super VGA resolution of 800x600, with 16-colors, at 56kHz. Disappointingly, neither system variant includes video BIOS support for this mode, seemingly precluding its use in Windows 3.0/3.1 and GeoWorks/NewDeal Office, where graphical corruption and/or error messages result if attempted.

Just for laughs I have GeoWorks Ensemble Pro configured for 800x600x16 on my Tandy 1000 HX with an OAK VGA card, but of course GeoWorks 1.x is pretty useless. Now you have me wondering if NewDeal/Breadbox would run on it at all on a V20-equipped machine; I have 1MB of EMS RAM, it'd be fun if I could actually get networking to work.
 

Cloudschatze

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Purportedly, NewDeal Office 2000 and BreadBox Ensemble have 386 dependencies. I've admittedly never tried the latter, but was unable to get the former to work on my 286-based systems, and so settled with NewDeal Office 3.2a instead.

I'm surprised to hear that the performance of GeoWorks Pro is so poor on your HX. I'm running it in 800x600x16 on an RL system (w/VGA expansion), which, despite having a slightly faster 8086 (as MHz comparisons go), completely lacks EMS. Notwithstanding, I find the DR-DOS 6.0/GeoWorks combination to be fairly respectable on it. I think I've developed a high tolerance for sub-performant systems though, so there is that... :)

But, now I'm curious. How does it compare to the performance I'm getting with the RL?

 

Eudimorphodon

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Purportedly, NewDeal Office 2000 and BreadBox Ensemble have 386 dependencies. I've admittedly never tried the latter, but was unable to get the former to work on my 286-based systems, and so settled with NewDeal Office 3.2a instead.

Maybe for laughs I'll try NewDeal 3.2a, then. If it doesn't actually use 286 protected mode then there's probably nothing stopping it from working on the HX.

I'm surprised to hear that the performance of GeoWorks Pro is so poor on your HX. I'm running it in 800x600x16 on an RL system (w/VGA expansion), which, despite having a slightly faster 8086 (as MHz comparisons go), completely lacks EMS. Notwithstanding, I find the DR-DOS 6.0/GeoWorks combination to be fairly respectable on it. I think I've developed a high tolerance for sub-performant systems though, so there is that... :)

It's probably in large degree a case of limited tolerance, although I'm mostly just referring to the fact there's not much in GeoWorks 1.x that makes me want to spend much time with it. Honestly I'm sort of impressed how usable screen updates are with the SVGA driver, it runs plenty fast to play Tetris on, and the Geoworks Write word processor *does* seem to be fast enough to keep up with normal typing. (I expected it to be *lot* more sluggish than CGA, but whatever additional slowness there is is counterbalanced by the fact it's *so* much better to look at.) But, still, if I was actually going to use the HX to bang out a letter I'd probably just use a text mode word processor because you do feel the pain with rapid cursor movements and scrolling. GeoWorks does do a decent job printing to my Apple Imagewriter over serial, although I'd never describe it as fast.

If New Deal actually runs well enough to do a stupid pet trick like run an IRC client then I might have an excuse to play with it more.

But, now I'm curious. How does it compare to the performance I'm getting with the RL?

Just panning around a little in the video and comparing things like how quickly they display clip art in the scrapbook it looks like their effective performance is actually pretty close. I assume you're running a newer version so it's probably not quite apples to apples, but it looks like at worse it's probably about comparable to the difference TopBench claims between the machines. (TopBench gives my machine an 8, an RL is an 11, which puts it about 72% as fast.)

I am curious about how you seem to be able to fire up TGA games on the built-in video. Are you running the vswitch utility on the Oldskool archive to do that? Alas there's no way that's going to work on the HX, as it seems to rely on the onboard graphics being in the "768k" configuration.
 

maxtherabbit

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my AVGA1 based Everex branded card supported 800x600 16color out of the box, at least in Windows 95
 

Cloudschatze

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my AVGA1 based Everex branded card supported 800x600 16color out of the box...
That's consistent with what I've seen as well. That is, video BIOS 1.00.07, which is what the RAMBIOS utility loads, appears to be the version that most of the discrete AVGA1-based cards are using. I find it odd that Tandy opted for lesser functionality in the RLX systems, and wonder if it might have been intentional.

Just for the sake of completeness, here are all of the additional video modes gained on a Tandy 1000 RLX system through use of the RAM-based BIOS utility:

Mode 54, 132x43, 16-color (text)
Mode 55, 132x25, 16-color (text)
Mode 56, 132x43, Monochrome (text)
Mode 57, 132x25, Monochrome (text)
Mode 58, 800x600, 16-color (graphics)
Mode 59, 800x600, Monochrome (graphics)
 

Cloudschatze

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So, here's a funny thing...

In my experience, the Tandy 1000 RLX-A and RLX-B have always largely been differentiated by the performance of their video chipsets. In both measurement and general practice, the RLX-B's AVGA1 chipset performs roughly 25% "faster" than the NCR 77C20 chipset in the RLX-A. This difference is especially apparent in VGA-based titles, to the extent that, of the two, the RLX-B makes for a considerably better gaming system.

Having said that, I'm finding that the 800x600 16-color mode completely flips the script from a productivity perspective, especially concerning Windows, and to a lesser extent, GeoWorks/NewDeal Office. At this resolution, the "slower" NCR chipset of the RLX-A noticeably excels - several drawing/redrawing operations are near-instantaneous, and the overall performance is objectively better. I'm not entirely sure why this is, but the elephant in the room is certainly the fact that the 77C20 has 32-bit access to its video memory, compared to the 16-bit access of the AVGA1.
 

dr.zeissler

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I can't find my original harddrive for my T1000RL/HD. So I will go for the test sample of the XT2SD and takeout my XTIDE.
Then I have to solder the LPT-Port to get a real LPT for my LTP2SCSI Cable. I have no Jazz only a SCSI-Zipdrive, but I also have an external BluSCSI, perhaps this is a option too. We will see.
 

rmay635703

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This makes me wonder if a method of populating 512k of vram is possible, my AVGA isa cards have 512k, not sure why the bios rom on the Tandy couldn’t be extracted and updated.

Tandy went to great lengths to cripple 1000 series systems, the fact that the RLX has addressing disabled so high density ram won’t work is a good example, alongside the ideotic smartdrive XT ide interface
 

dr.zeissler

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Testing the A2K-BB/286/8 catalog against the T1000 equipped with ET4K.
Is it true that the V20 is faster than 8086 ? Benchmarks indicates the V20 is faster.
 

Cloudschatze

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This makes me wonder if a method of populating 512k of vram is possible, my AVGA isa cards have 512k, not sure why the bios rom on the Tandy couldn’t be extracted and updated.

The NCR77C20 chipset of the RLX-A could potentially support a 512K configuration with some modification, but I understand the AVGA1 chipset of the RLX-B may be hard-limited to just 256K? Are your 512K cards based on the AVGA2, perchance?

I haven't felt particularly constrained by the 256K VRAM in either RLX though, to be honest...







NDO_RLX.PNG


Yeah, take that, DeskMate!
 
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