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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.


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.


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.



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.


"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.

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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PGC

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    PGC

    Professional Graphics Controller

    The IBM Professional Graphics Controller (sometimes called Professional Graphics Adapter or Professional Graphics Array) was, being released in 1984, one of the very first graphics options for the IBM PC to have 2D/3D hardware acceleration. The PGC consisted of two full length cards and one half length card, bolted together like a sandwich. The PGC takes up two ajacent 8-bit ISA slots with spacing based on the PC/XT, so the card can not be used with the original IBM 5150 PC. The card was intended for CAD (Computer Aided Design), and a PGC with matching monitor was priced at about $4500 USD (of 1984 currency).
    Natively, the PGC only supports the resolution of 640*480 pixels with a palette of 256 colours (selectable from a total of 4096). If jumper W1 is altered, CGA emulation is enabled, but all the pixels in med-res mode are quartopled in size, making up the resolution of 640*400 (pixels in high-res mode are just doubled to make the same resolution).
    The core of the card is the 8088-2 CPU running at 8MHz, it reads commands and data from the input buffer and writes graphic data to the framebuffer. In addition, it also handles the settings for the hardware acceleration. For the hosting computer to do anything with the PGC, it sends commands to the card's input buffer/control area, which is mapped in the memroy map of the host computer. Those commands are processed by the 8088-2, in either ASCII or HEX mode. There is no other way for the host PC to control the PGC.
    The PGC was made untill 1987, but due to it's high price and slow graphics processing, it was never an option for the mass-market, EGA was more appealing there. This was not strange since IBM never intended the PGC for the mass-market after all.
    Output

    The PGC outputs with either 640*480, or 640*400 resolution at 4-bit RGB. The interface is just the same as 9-pin VGA, with the only difference that the PCG uses composite sync instead of H/V sync. Despite this, most VGA monitors will be able to understand the signals from the PGC when a 9-to-15 pin VGA cable is used.
    [wiki]Category:ISA cards[/wiki]
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