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Forum Rules and Etiquette

Our mission ...

This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.


Rule 1: Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.


Rule 2: Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.



Rule 3: Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.


Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.


Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.


Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.


New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.


Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
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To V20 or not to V20...

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  • Chuck(G)
    replied
    This is a subject that has been discussed in detail by many publications since 1985. The reasons for the V20 running faster than the 8088 at the same clock speed have also been discussed--even in NEC's own literature. Lawsuits by both NEC and Intel on this chip family have also been detailed.

    Leave a comment:


  • modem7
    replied
    At [here] is an example of a problem that resulted from upgrading an 8088 to a V20.

    Leave a comment:


  • vwestlife
    replied
    Originally posted by voidstar78 View Post
    swapping the chip can change the speed? from 4.77mhz to 8mhz?
    No, swapping from an 8088 to a V20 or vice versa does not change the clock speed. The Tandy 1000SX runs at 7.16 MHz.

    Leave a comment:


  • voidstar78
    replied
    Ah, I forgot about Battle Chess, that was a nice title - my daughter might like that, she's into chess.

    BTW - swapping the chip can change the speed? from 4.77mhz to 8mhz? Just a simple chip swap, no dips or jumpers? Or is it just some efficiency of the chip, makes it effectively like it's running at 8mhz? I just thought the crystal/clock had to be modified somehow, wasn't clear how a chip swap changed the actual rate.

    Leave a comment:


  • Patrick Bureau
    replied
    well, I have a tandy 1000sx and before I was running an 8088, I could barely run some games (like battle chess for example) I put a D70108C-8 (aka v20-8Mhz and a D8087-1 (aka 8087-10Mhz) and its the best thing I could do to this old box, now I have not found a period game I am not able to play so far. so I am all for the authenticity, but with usability, no one can see the chip and if someone bought it from me, I would provide the original chip for them to downgrade the machine if they so desire.

    Leave a comment:


  • digger
    replied
    I don't know if this also applies to the V20, but I clearly remember that once we'd replaced the 8086 CPU in my Dad's Olivetti M24 with a NEC V30, some games started showing certain animations that were disabled before the upgrade. I remember this being the case with Space Quest III and the CGA/Tandy/EGA version of The Secret of Monkey Island. In the latter game, when you walked into the SCUMM Bar™, you would see a pirate swinging back and forth on the chandelier if the game was running on a V30 CPU. Before the upgrade, the chandelier would be hanging still without a pirate in it.

    I'm still not sure whether these games enabled these graphical details on the basis of timing loops, or by checking whether certain 186+ instructions were present. Probably the former.

    Leave a comment:


  • kdr
    replied
    I have a 5150 that I keep in its original condition (8088 CPU, MDA/CGA video, no fixed disk) and a generic Turbo XT clone that gets kitted out with all the extras like a V20 CPU, EGA video, etc. Best of both worlds!

    Leave a comment:


  • compaqportableplus
    replied
    I generally install a V20 in the machines I use frequently. It’s just enough performance increase without being too much (like a full-blown accelerator). I want my PC or XT to still run at a realistic speed, and the V20 is pretty damn perfect for that in my opinion. I’ve never had any compatibility issues with it personally.

    Leave a comment:


  • vwestlife
    replied
    Originally posted by voidstar78 View Post
    Re, VGA in the 5150: You're right some early titles don't work with the VGA card.
    Some VGA cards came with a utility program that drastically improved their CGA (and MDA) compatibility. For example, VGA1024.EXE for Western Digital / Paradise VGA chipsets:

    https://www.vogons.org/viewtopic.php?t=52222

    Leave a comment:


  • Krille
    replied
    Originally posted by TheDrip View Post
    I installed a V20 in my 8088 machine to run a different version of the XT-IDE firmware. IDE_AT instead of IDE_XT which made for a 50% boost in throughput for my CF card.

    IDE_AT only requires 186, not 286 it turned out.
    You must be misremembering. Not only do the AT-builds, as Eudimorphodon already mentioned, call system BIOS functions not available on XT BIOSes, they are also using undocumented CPU instructions not supported by the NEC V20.

    Leave a comment:


  • voidstar78
    replied

    Thanks guys! I'll save my V20 for if I ever pick up another 5150, and I'll leave this one alone as-is. I can do some electronics work (see here) and I've lapped a few CPUs in my day during my "extreme PC" adventures (and they all still work to this day! also took my Pentium D to 4.1 GHz in '06 ). Swapping this 8088 seems like easy work. But that was a good way to put it: losing some earlier compatibility to gain some later capability.



    For instance, SimCity is basically unrunnable for me at 4.77mhz. Same for King's Quest IV. They do run, but painfully slow. Lemmings is sluggish, but tolerable. And I'm ok with all that, as any title past about 1988 is just lucky that it runs at all IMO. I'm not sure if the V20 would make these all more tolerable. Besides, absolutely, I can't give up my 5150caxx compatibility And I'm ok with my MODs being played at 9-11 khz instead of 20-22.



    Thanks Eudimorphodon for covering all the questions! Wow, ~$15 for a V20 even then !? (well, and then shipping - another $15 maybe?). About the cost of one $29.95 software title I was thinking it would be over $100, possibly 2. But I suppose at that price, you'd better just upgrade to an AT. I already had a Tandy 1000 in '87, but if I had a stock 5150 then I'm not sure if I would have made the call to try the V20. I might have, as a BBS operator, to give DESQView a little better chance (as I'd like to use Turbo Pascal while folks were connected - and the idea back then of having TWO computers, no way, could barely afford one!). But I can't remember if I got a '486 before 1990 or not (I know I skipped the 386s, spoiled jumping straight to a '486dx50).


    Re, VGA in the 5150: You're right some early titles don't work with the VGA card. Specifically, Astro Doge won't work with my VGA card - I'm really curious why though, and bummed since it's a pretty decent game for '82. And King's Quest 1 switches color palettes between when I have the CGA card (yellow/green) and then the VGA card (cyan/white), so little things like that happen. [ there was a video once on "what CGA color palette did Sierra intend for KQ1 to be in?" and I'd say the answer was none-of-the-above but if I had to pick, I prefer the yellow/green for that one ]. You're right also that curiously, some .COM programs I've tried just freeze up my 5150 - and I assume it's some "errant" opcode, some '186 thing. Nothing real sacred about what instructions can end up in a .COM. I should have kept a better list/track of those incompatible titles, I tended to just delete them.


    I don't mind the MDA/CGA/VGA adapters (and using the CGA card), but the phase isn't perfect and the font ends up slightly wavy (maybe it's the cable?). Plus when I shut things down, that adapter is one extra thing to remember to turn off. I'm kind of on the hunt for some more MDA game titles (besides text adventures). Something like Kroz should have been possible on the MDA early on. I suppose Castle Adventure should support MDA? [ was thinking of adding a section about what titles to use if all you had was MDA - '82 WordPerfect is fun for a bit, and BEAST was actually '84 - surely there was some interesting non text adventure game in '83 ? ]



    Although, the increased performance for the XT-IDE with a V20 is appealing. But that's a good point, it is already faster than "stock"/contemporary performance, so I can just appreciate that. I hope the XT-IDE doesn't also simulate the gradual accumulation of bad sectors Speaking of that - is DEFRAG necessary or helpful on the XT-IDE ?




    And I especially liked the point about not taking for granted how many times you can swap chips in and out (and yes, each time is a risk of some bent pins -- which aren't the end of the world, unless they snap off -- and the end falls somewhere down on the motherboard). I was nervous about even swapping expansion cards on this antique, but I'm mostly over that now. I guess an extreme thing to do is to have a toggle switch between the 8088 and V20? Seems like some elaborate board could be made, to slide into the 40-pin DIP - put your two processors on that board, have a little switch to alternate between them? Would just that extra little distance skew timing? Hmm... Won't be my project, but would be interesting to see [ the chips could even be vertical to save space? maybe something like this was already done? ]





    Below: Kids, don't try this at home.
    lapped_athlon.jpg
    Attached Files
    Last edited by voidstar78; September 2, 2021, 08:01 AM.

    Leave a comment:


  • Eudimorphodon
    replied
    Originally posted by TheDrip View Post
    I installed a V20 in my 8088 machine to run a different version of the XT-IDE firmware. IDE_AT instead of IDE_XT which made for a 50% boost in throughput for my CF card.

    IDE_AT only requires 186, not 286 it turned out.
    I'm pretty sure in the pre-built binaries the "_XTP" ones are the canonical versions you want to use on V20/30/40s, not _AT. The docs say:

    USE_AT

    Assembles code targeted for AT systems. For example, AT-builds always operate in Full Operating Mode. Another difference is that AT-builds use some BIOS functions that are not available on XT systems
    But I guess if it's working for you that thing about using AT-only BIOS functions must not be entirely true. I can attest that the _xtp version gives me the same speed boost over a plain _xt build.

    Leave a comment:


  • TheDrip
    replied
    I installed a V20 in my 8088 machine to run a different version of the XT-IDE firmware. IDE_AT instead of IDE_XT which made for a 50% boost in throughput for my CF card.

    IDE_AT only requires 186, not 286 it turned out.

    Leave a comment:


  • Chuck(G)
    replied
    My exposure to the NEC V20 was through the NEC USA in Natick, MA. I was developing software for the 8080 emulation mode and got some help from them. I may even have an issue or two of their MicroNOTES publication. I've used it with NICs that required the 80186 instruction set quite successfully.

    Leave a comment:


  • bladamson
    replied
    The only reason I installed one is because some TSR (I think it was the PLIP) driver needed the 186 instruction set support. Otherwise I don't think the 10% speed boost amounts to much.

    Leave a comment:

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