Announcement

Collapse

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.
See more
See less

IBM 5155 - "Insufficient memory to run"?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    Originally posted by bvcderrttyyhjjjk View Post
    "Sixpak" doesn't really seem to be a thing that I can find on eBay around here at the moment. What would the difference and advantage/disadvantage to an original card in your experience?
    "Six Pack" was simply AST's name for a line of multifunction boards they sold that combined memory expansions with I/O ports, calendar chips, whatever. There were a lot of companies that made similar boards, I just don't remember the names for any off the top of my head. (And also on eBay such boards, especially from more generic manufacturers that aren't clearly marked, might not be listed as anything but "expansion card".) There's basically *no* disadvantage to one of these boards compared to the IBM board; memory is memory, and getting additional functions on a single card means you occupy fewer slots and, potentially, save a wee bit of power.

    Personally I think you might be making too big of a deal about the motherboard "modification". I'm sure there's other people on here that can speak more directly on the kinks, but if the instructions I found for it are accurate it's completely reversible and only involves plugging some chips into sockets, no soldering. It counts as a "period correct" modification because the board was built to accommodate the larger chips and instructions for DIY memory expansion of IBM products aren't exactly a new thing.

    Here is the no-brainer off-the-shelf modern solution if you want something you can just cash-and-carry. Clones of this board are sold on eBay, just be careful because some are designed better than others. The Lo-Tech one seems to have a pretty good reputation. With this board you can expand your 5155 up to 704k conventional *and* add some upper memory blocks useful for running DOS 5 and later with the right drivers.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot

    Comment


      #17
      Originally posted by Eudimorphodon View Post
      I'm sure there's other people on here that can speak more directly on the kinks, but if the instructions I found for it are accurate it's completely reversible and only involves plugging some chips into sockets, no soldering.
      Not entirely correct. A jumper has to be installed between pads 1 and 2 on jumper block E2.
      PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

      Comment


        #18
        Originally posted by Eudimorphodon View Post
        ...I'm sure there's other people on here that can speak more directly on the kinks, but if the instructions I found for it are accurate it's completely reversible and only involves plugging some chips into sockets, no soldering...
        Originally posted by Stone View Post
        Not entirely correct. A jumper has to be installed between pads 1 and 2 on jumper block E2.
        The jumper at E2 can be replaced with a wirewrap to a pair of pins on the bottom of the prom in socket U44.

        3. Remove the IC installed in the socket labeled U44.
        4. Install a jumper wire from pin 1 to pin 8 on U44. To avoid making any changes that cannot be removed later, the jumper can be wrapped directly onto the pins of the IC. Run this wire on the underside of the IC so that the wire is held in place. Reinstall the chip with the jumper in place. The IC may sit slightly higher in the socket, but make sure that it is seated properly.
        I wholeheartedly agree with the following;
        It counts as a "period correct" modification because the board was built to accommodate the larger chips and instructions for DIY memory expansion of IBM products aren't exactly a new thing.
        I have a 5155 that I've owned since bought brand new in 1985. My Dad and I did the 640K mod about two months after it was bought. We did the same mod on my Moms 5160. We did this mod based on instructions received at an IBM PC CLUB meeting in San Jose, CA!! So, many, many others were doing it. MUCH cheaper than memory expansion cards. I believe the chips required cost about 50 bucks at Fry's Electronics at the time.

        Comment


          #19
          Originally posted by bvcderrttyyhjjjk View Post
          ..."Sixpak" doesn't really seem to be a thing that I can find on eBay around here at the moment. ...
          Try This Ebay Link

          Although, I still recommend the 640k Mod, This one is nice due to the inclusion of an RTC, a serial port and a parallel port. All useful on a 5155. And the seller includes a nice description and offers to provide tech help getting the thing working! Plus, he has 100% positive feedback! Shipping seems a bit steep though

          Comment


            #20
            Originally posted by ibmapc View Post
            I think I may have had that exact card in a 5150 back in the mists of time.
            My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot

            Comment


              #21
              For my own 5155, (since I'm not very cluey about file transfers via the ports in DOS, though its easy with my SOL-20 with CP/M it seems with PCPUT & PCGET via the serial port) and I'm better with the hardware side of things than any software, I decided the easiest thing to do was to install a dual 3.5/5.25 floppy drive in one bay of my 5155, with the "Unique floppy controller board" and an vintage Seagate HDD in the other bay. My computer also has the AST 6 pack plus card and the smaller IBM isa memory card too to get 640kb.

              On the HDD I have DOS 3.3 and a number of other programs I use such as IBM's assembler and the usual DOS utilities and various other programs as there is plenty of space on the HDD. Also I put Windows V1.0 on it and Harvard Graphics. DOS 3.3 was the first version to support the 1.44Mb floppy. Also I have Procom for terminal emulation and Borland's Brief as a text editor to write assembly programs. So its all very handy having it right there on the HDD.

              But the convenient thing is I have an external 1.44 floppy drive on my other more modern computers so I can easily get files, programs & data etc in & out of the 5155 that way.

              There will be better ways to do it via the ports, but this hardware way "worked for me" and I have little trouble with it. The 5155 is not original though, but the two belt drive original IBM floppy drives might not have been wonderful either. I keep these with the computer & the original controller card, just in case one day I want to put it back to original. The power supply in the 5155 is up to running the HDD.

              It was an interesting process to fit the HDD, it requires a low & high level format and I had to try a couple before I found a good drive unit, but it has been reliable for a couple of years now.

              One thing I learnt the hard way was that the cheap external 1.44Mb USB floppy drives coming out of the far east are often really bad and corrupt files. I would advise buying something like a 1990's to 2005 vintage new old stock brand like IBM or Imation drive in its original box, cost more, but you won't have any troubles. I struggled for some weeks trying to work out why the programs I transferred via one of the cheap drives were corrupted. I only found it because I had jpeg images on a disk in the cheap 1.44 drive and noticed over time the pixels in the image were becoming corrupted, without that visual indication, I would probably still be working on it trying to find out what the heck was wrong.
              Last edited by Hugo Holden; April 6, 2020, 06:50 PM.

              Comment

              Working...
              X