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The quest to use an Apple II+ as a viable VT100 terminal...


Streck
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At first, I was content to use my II+ as purely a game machine, but the perfectly-working Videx VideoTerm card led me to explore various applications involving 80-column text. One of these was to use it as a terminal to a Linux box.


There are, so far as I've found, two programs that might fit the bill: Kermit (Kermit-65, to be exact, v3.87), developed by the well-respected cabal at Columbia University, and DCOM 3.3, an ambitious effort by then-student at UCSD Jim Hayes. Both are available on the Asimov FTP site. Other communication apps like ASCII Express or ProTerm either don't run on the II+ or don't offer anything better than VT52 emulation at best.


Results from each have been mixed.


DCOM's Videx driver was all written by Hayes himself, and its initial implementation is, well...


FKTdASk.jpg


No, the vertical sizing on my monitor doesn't need adjustment - the VideoTerm stays obediently within the screen in all other applications. For whatever reason, Hayes' driver puts the VideoTerm's text out of bounds. The input bar for the IRC client is well below the white bar at the bottom.


The only way to compensate for this is to shrink the vertical size, which yields a distracting effect where text gradually gets longer as you go from top to bottom - and also renders the top inch or so of the screen unused. Look carefully:


Hx3XCWw.jpg


This, of course, has to be reverted back when I'm finished, lest all other games and apps look squished.


Hayes posted two different patches for the driver, but the first one seems to completely break the process - DCOM just asks me to switch to my output device, as though it doesn't even know the VideoTerm card is there - and the second produces garbage characters combined with an out-of-whack vertical sync. Not good.


On top of that, DCOM leaves, as far as I can tell, absolutely no way for you to input capital letters unless your II+ has the shift-key mod, or even up/down arrow keys, which are vital for certain UNIX/Linux programs such as Lynx.


So, it was time to turn to Kermit. Initially, it looked very promising - none of DCOM's awful video stretching! The display was as perfect as anything I'd seen on professional-quality applications like Magic Window II.


My joy was short lived...


OlgCkGU.jpg


The issue here seems to be with the VT100 emulation itself. The Kermit manual does in fact say that the emulation is not complete, but that seems to be an understatement. The scroll region in any IRC or chat program is limited to the bottom few lines, rendering those programs useless. You can see where the ASCII art that's supposed to say "irc.choopa.net" just writes over itself at the bottom. And there doesn't appear to be any setting in Kermit to tweak in order to overcome this.


It's quite a shame, because Kermit is wonderful in all other respects. The full character set is available for you to input (although, as with DCOM, I haven't determined how to input up/down arrows, or even if that's possible) and the VideoTerm display is top-notch. In scouring the Internet, I did find old USENET posts and scans of Washington Apple Pi showing evidence of a v3.88 of Kermit-65 - but that version seems lost to the ages... and, even if it were found, there's no guarantee that it would possess a more complete VT100 emulation. I also came across posts about NovaTerm for the C64 and other emulators that claimed to do VT100, but, like Kermit, fell short. Apparently this was not an uncommon issue back in the day: "true VT100" didn't always mean that!


So, I'm curious to know if anyone else has embarked on this crazy quest, or at least if they have any advice to share. I'm willing to accept the possibility that the II+ is juuuuust far enough on the trailing edge of technology to make what I'm after impossible... but I'm not willing to concede that until I've exhausted my options (short of writing my own Videx driver, because frankly, that's beyond me).

Edited by Streck
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Hi,

 

Will Modem MGR work on your Apple II+?

 

It's a fantastic terminal emulator, and features VT220 emulation. I use it on my //e, but I'm not sure if it requires the extra RAM or not.

 

http://apple2.org.za/gswv/a2zine/Utils/MMGR_PDOS_DSK.zip

 

 

It'll run, I just can't have VT100. From the documentation:

 

"VT220/VT100 emulation runs on the ProDOS version only and requires a IIGS, //c, or //e with Apple 80-column capability. This emulation will not run on the DOS 3.3 version or on a II+ or with other video cards."

 

:sad:

Edited by Streck
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It'll run, I just can't have VT100. From the documentation:

 

"VT220/VT100 emulation runs on the ProDOS version only and requires a IIGS, //c, or //e with Apple 80-column capability. This emulation will not run on the DOS 3.3 version or on a II+ or with other video cards."

 

icon_frown.gif

Ah, that's a shame. I do really like that one.

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I got as far as creating all four floppies for it, and running it, before discovering what I could've known if only I'd read the docs. :P

 

(Also, I see you're in CT as well. Head up route 8 to Carbone's Market in Torrington for the biggest sandwiches you've ever had.)

Edited by Streck
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So, here's what I have so far:

 

ASCII Express - VT52 only

MODEM.MGR - no VT100 on II / II+

VisiTerm - no VT100

Kermit - incomplete VT100

DCOM - bad Videx driver (two patches posted; neither worked for me)

ProTerm - indeterminate. II / II+ version not available for download; can do VT100, but unknown if this extends to II / II+ with Videx

Z-Link - no II / II+ support

 

The search continues...

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I got as far as creating all four floppies for it, and running it, before discovering what I could've known if only I'd read the docs. icon_razz.gif

 

(Also, I see you're in CT as well. Head up route 8 to Carbone's Market in Torrington for the biggest sandwiches you've ever had.)

 

I'll definitely check our Carbone's. I have a friend in Torrington so I go up there occasionally.

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  • 1 year later...
  • 1 year later...

Wow.  Imagine finding this 34 years later.

 

The Videx VideoTerm driver caused me no end of grief.  I suspect there were a few different versions of the card's hardware.

 

It had an Hitachi video chip that required programming all the video timing values directly to the chip.  The chip also needed all read/write accesses to be synchronized to the vertical blanking period.  Without synchronization, you'd get timing artifacts on the screen where the scan would be interrupted by a few clock cycles. 

 

The architecture of DCOM was designed to support a mix of serial cards, many without interrupt support.  This precluded me from using the I/O routines provided by the Videx ROM, which would cause input characters to be dropped from the serial card. ?

 

Of course, the 55 year-old me would have designed it differently. ?

 

-Jim Hayes

Edited by TahoeJimbo
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I did that for a few months. Tried to find a terminal program to work with Linux after I got my apple ii plus. PRoblem seemed to be most programs wanted a 65c02 or something. I'm surprised that since the vt-100 was introduced in 1978 that by 1983 we didn't have a good group of programs. Then again I searched a few magazines about that. Found a few programs that once again. Was not for the apple II plus or couldn't find them in an archive anyplace.

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2 minutes ago, ussexplorer said:

I'm surprised that since the vt-100 was introduced in 1978 that by 1983 we didn't have a good group of programs.

Doing a faithful VT100 implementation wasn't too taxing, though emulating all of the bugs and bizarre edge cases was.  That's where DCOM ruled the roost.

 

The real issue was getting the serial performance up without dropping characters.  (Apple never really embraced hardware interrupts until the //gs.)

 

DCOM worked well on the Apple //e and //c because it could poll the serial port ~1000 times a second, even while drawing on the internal 80 column screen.

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Some of that software that doesn't want to run on a II+ may if you just drop a 65c02 into it in lieu of the 6502.  Unfortunately, Clone+ is out for repairs, or I'd be inclined to try.  Speaking of which, I must get to and see if I have any of the replacement logic on hand.

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I was wondering about that. Putting in jut a 65c02 and see if that would satisfy the few terminal programs that required a 65c02. Since several upgrade exist for the apple ||+ include the 65c02. For instance one forum talks about using a 65c02 in apple II+ to run ProDos 2.0.3. Posted from about 17 years ago. So my guess before they removed the requirement on prodos I guess. It does also explain some 65c02 won't work in the II+. Not sure why.  The link so I can give credit to credit do and you can read the article. https://comp.sys.apple2.narkive.com/vHszPodU/65c02-in-an-apple-ii 

One more thought was to bad they didn't get the memory bank switching the same in the IIe. That seems to be another issue. Thus, even if you have say a Ram factor card. Some programs that require 128k will not work unless they have built in support or a patch from Either the company who makes the memory card or a patch from the software. Well something like that.

Edited by ussexplorer
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On 3/14/2017 at 2:30 PM, Streck said:

So, here's what I have so far:

 

ASCII Express - VT52 only

MODEM.MGR - no VT100 on II / II+

VisiTerm - no VT100

Kermit - incomplete VT100

DCOM - bad Videx driver (two patches posted; neither worked for me)

ProTerm - indeterminate. II / II+ version not available for download; can do VT100, but unknown if this extends to II / II+ with Videx

Z-Link - no II / II+ support

 

The search continues...

 

I have old versions of ProTerm, if you want to try them. Is your system 64K, 48K, or something else?

 

Are you using a genuine Videx card?

Edited by GameGeezer
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  • 1 year later...

I hate to go grave-rob such an old thread on a forum I have never used before, but I'm running ProTerm 3.1 DEC VT-100 emulation for a Raspberry Pi 4 on an enhanced Apple //e, and I have the exact same issue described at the end of the original post. 

Did anybody ever solve the issue? I would hate to discover after months that using my //e as an IRC machine is impossible.

 

-null

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  • 8 months later...
On 5/31/2020 at 9:36 PM, TahoeJimbo said:

Wow.  Imagine finding this 34 years later.

 

The Videx VideoTerm driver caused me no end of grief.  I suspect there were a few different versions of the card's hardware.

 

It had an Hitachi video chip that required programming all the video timing values directly to the chip.  The chip also needed all read/write accesses to be synchronized to the vertical blanking period.  Without synchronization, you'd get timing artifacts on the screen where the scan would be interrupted by a few clock cycles. 

 

The architecture of DCOM was designed to support a mix of serial cards, many without interrupt support.  This precluded me from using the I/O routines provided by the Videx ROM, which would cause input characters to be dropped from the serial card. ?

 

Of course, the 55 year-old me would have designed it differently. ?

 

-Jim Hayes

 

Well, I hardly know what to say.  Seeing a response from DCOM's original author was not what I expected upon revisiting this post of mine.  I will say that, in spite of the challenges I had with it, I definitely appreciate both the program itself and the effort that went into it.  Not a project for the timid, and one could feel your tenacity through those old newsgroup posts about the VideoTerm driver... ?

 

Since I wrote my original post, I've acquired a second VideoTerm card - no clue if its hardware is the same version as my other one, but I can certainly try it, with and without your patches.  Just need to pry out the inverse-video chip and move that over.  (I'd love to experiment with an array of VideoTerms, but even on eBay they're not exactly common these days!)

 

I do also have a //c and a Laser 128EX (so, basically another //c) on which I haven't yet tried DCOM.  I've found 1200 baud to be my limit on the II+ but I should be able to get better speed on the other machines.  I imagine I'd still be using DCOM the most on the II+, though.

 

Honored to have you here!

Edited by Streck
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On 6/2/2020 at 5:01 AM, Aunty Entity said:

Some of that software that doesn't want to run on a II+ may if you just drop a 65c02 into it in lieu of the 6502.  Unfortunately, Clone+ is out for repairs, or I'd be inclined to try.  Speaking of which, I must get to and see if I have any of the replacement logic on hand.

 

One of the reasons I have the II+ is because I sometimes play certain games that require a 6502 and refuse to load with a 65C02.  Plus, for purist/sentimental reasons, I'm loath to replace the original CPU anyway.  ?

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On 6/8/2020 at 11:43 AM, GameGeezer said:

 

I have old versions of ProTerm, if you want to try them. Is your system 64K, 48K, or something else?

 

Are you using a genuine Videx card?

 

Yup, it's the genuine article.  Copyright year on the chips is 1981; my II+ has 64K with a Microsoft RAMCard.  I did see GameGeezer's link for ProTerm - I can't remember why I didn't try it a few years ago.  That site has version 1.1 and it seems like I should try the earliest versions first.  But if you have any versions that you'd like to throw up disk images for, that would certainly be welcome!

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18 hours ago, Streck said:

 

One of the reasons I have the II+ is because I sometimes play certain games that require a 6502 and refuse to load with a 65C02.  Plus, for purist/sentimental reasons, I'm loath to replace the original CPU anyway.  ?

Slightly off topic, but what games are you talking about? I've seen many generic references like this about software that will run on a 6502 but won't run on a 65C02. But never found any references to specific titles.

Edited by nick3092
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1 hour ago, nick3092 said:

Slightly off topic, but what games are you talking about? I've seen many generic references like this about software that will run on a 6502 but won't run on a 65C02. But never found any references to specific titles.

 

Offhand, some of the early Atarisoft titles such as Burgertime and Centipede.  They won't run on my //c or Laser 128EX but my ][+ handles them just fine.

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18 minutes ago, Streck said:

 

Offhand, some of the early Atarisoft titles such as Burgertime and Centipede.  They won't run on my //c or Laser 128EX but my ][+ handles them just fine.

Interesting. The widely available WOZ versions of those games boot fine on my //c and Floppy Emu. But it's possible they are a later version meant to run on newer machines.

 

I know some early games would do checksums on the boot proms as part of the copy protection, and so they would fail on newer machines like the //c. I believe the original release of Choplifter was one of those games. 4am wrote a utility called anti-m that intercepts and patches those checks on the fly so you can boot those disks on machines they would normally fail on. If you ever wanted to try those games on your //c or Laser, anti-m probably would let you boot them.

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