Talk:IBM PCjr

message: Since the exchanges between Bptdude and Trixter seem to be done, can they either be removed or edited down a bit? Misoman 09:03, 7 February 2007 (UTC)
replies: text: I'd love that, but unfortunately doing so is against some wikipedia guideline that I can't remember at the moment. --Trixter 20:39, 7 February 2007 (UTC)
replies: text: Wikipedia:Talk_page_guidelines discourages editing or removing comments, but allows it if agreed upon by those involved. So I guess it depends on whether Bptdude feels there's value in keeping it all intact. There might be a couple snippets worth preserving, but with POV and grammar issues resolved I think much could be trimmed. By the way, for future reference, I hereby give permission for anyone to delete my comments in this section when they are no longer relevant. I don't want this section getting stuck here forever, too. Misoman 19:31, 12 March 2007 (UTC)
thread_title: Discussion cleanup?

message: The Tandy 1000's enhanced video modes were functionally identical to the PCjr, but differed slightly in how software addressed them. The same was true of the sound, since the Tandy also used the same sound chip, which was also used in the TI-99/4 and 4A computers. Rivaled the Atari POKEY? No way! Three simultaneous tones and one noise, with the noise being a choice of waveforms or 'white', which sounded like radio static.
Simple hardware modifications to the mainboard allowed a PCjr to run nearly all Tandy 1000 software with the enhanced video modes and sound.
IBM also sold a speech module, using the same TI speech chip in the speech module for the 99/4A, but IBM's implementation was much more limited than TI's, with very little PCjr software written to use speech.
3rd party upgrades often added a 'second story' on top of the main case, using a special sidecar expansion to connect the upper floppy drive bay and circuit board. These upgrades were mostly for expanding the RAM to 512K or 640K in addition to the second floppy bay. Some included other peripherals in the additional space since the RAM expansion didn't use anywhere near the full height of the expansion case.
The internal modem from IBM was pitifully slow. ISTR that at least one 3rd party made a 14.4 internal modem, but it may have required mainboard modifications to implement DMA.
The system had a 'last gasp' in Japan and Australia as the IBM PCjx in a black case (update: I've seen this in a white case) with two 720K 3.5" floppy drives and an extended keyboard. http://popcorn.cx/computers/ibm/pcjx/
Comment from iambk: The system could barely handle a 2400bps modem and I don't think a 14.4kbps internal modem was ever made for the PCjr.
The 300 baud modem was useless, really. I had a Hayes 1200 that worked fine on the serial port. I still have that modem, as it is unique also, in that it can take ascii text from the serial port and output morse code in standard audio, by flipping a toggle switch.
:Just for curiosity's sake, are you sure that the toggle switch was for switching to Morse? I had a Hayes Smartmodem 300, and Morse code was built-in to the Hayes command set with no need for a physical switch over. Requiring a switch seems like a step backwards in terms of design. -- Misoman 00:09, 9 January 2007 (UTC)
thread_title: More info

message: Article should make some mention of the PC Jx. Bastie 03:27, 24 February 2007 (UTC)
replies: text: Separate article exists at IBM JX. 2fort5r (talk) 10:36, 17 August 2009 (UTC)
thread_title: PC JX

message: "offered built-in color graphics and sound comparable to or superior to other home computers of the day." - I think we've established that this isn't true when compared to the C64 especially --MartinUK 19:05, 20 May 2006 (UTC)
thread_title: Capabilities

message: Failure in the marketplace
I removed the comment about the wireless feature of the keyboard. I remember articles in PCjr magazine about this. They were trying to use the keyboard from accross the room. This is typical of the gap between the designers and the wildly expectant market. In fact the keyboard worked great from only a few feet away, and the infrared eye was right in the front of the computer, usually less than a foot away. — Bptdude 01:58, 13 August 2006 (UTC)
thread_title:  Failure in the marketplace 

message: mine:
The PCjr had a limited amount of business software available on cartridge, including a PCjr version of Lotus 123 spreadsheet. The cartridge would be plugged in from the front, the computer would reboot, and automatically run, with the ability to load and save data by means of the floppy drive. Dedicated computers that run common office software have not been seen since.
yours:
The PCjr had a limited amount of business software available on cartridge, including a PCjr version of Lotus 123 spreadsheet. General usage entailed plugging in the cartridge from the front, prompting a reboot of the computer; the software would run automatically, with the ability to load and save data by means of the floppy drive.
my comment:
We don't need to say "General usage". You plugged in the cartridge, the computer rebooted. There was no other option. It was not software, either, it was firmware. And unless you can name me systems that have no OS but will run Microsoft Office from firmware, please leave my comment about "not been seen since" alone.
:My issue wasn't with "not been seen since", my issue was with "Dedicated computers that run common office software" which is awkward and not really correct. If you want to say that PCs that run cartridge software haven't been seen before or since, that's correct. But there have most definitely been "dedicated computers that run common office software" (dedicated word processors, most PDAs, etc.) --Trixter 15:15, 21 August 2006 (UTC)
thread_title:  First topic 

message: mine:
The PCjr had two joystick ports. There were only a few games that took advantage of this, but this allowed two player games, similar to modern game consoles. This is a feature not available on major brands computers since.
yours:
The PCjr had two joystick ports. There were only a few games that took advantage of this, but this enabled two-player games, similar to modern game consoles.
my comment:
Unless you can name even one major computer brand that sells a system with two joystick/game ports, please leave this comment alone.
:Tandy 1000 series, which lasted until at least 1990 and was most definitely more popular than the PCjr. Also Amstrad, in the UK. So your comment was technically incorrect, which is why I fixed it. Should I fix it again, or do you want to? --Trixter 15:17, 21 August 2006 (UTC)
thread_title:  Second topic 

message: mine:
The PCjr had a lightpen port. The lightpen worked as a mouse replacement. It was not very common, and the port was later used in combination with the serial port to use an optic mouse, which worked very well. Most PC mice for years used mechanical balls and optic mice are now more the convention.
yours:
The PCjr had a lightpen port, which worked as a mouse replacement. It was not very common, and the port was later used in combination with the serial port to drive an optical mouse, which worked very well.
my comment:
The lightpen and the lightpen port were two different things. The lightpen port was used as an input port for some other devices. The optic mouse was similar to those used in workstations with a special reflective pad that had a grid. That PC's mechanical balls for years before only now converting back to optic is true and worth mention about the PCjr design. Please leave comment alone unless you can justify why.
:What you originally wrote doesn't make sense. Are you saying that a mechanical mouse that used the lightpen port is the same as an optical mouse? That's obviously not true... Are you saying that PCs didn't use optical mice until recently? That's also not true; in fact, the first widely-available mouse for the PC was from Mouse Systems and was optical (used the metallic pad you metion) and was available before the first Microsoft mouse (mechanical) was. So I edited that passage because I'm not really sure what you're trying to prove. --Trixter 15:32, 21 August 2006 (UTC)
thread_title:  Third topic 

message: mine:
The PCjr could be purchased with full manuals that included BIOS source code and all hardware schematics. This made for the popularity of hobby/home modifications and a number of small shop hardware upgrade companies, eventually being absorbed by PC Enterprises. Such open design is unheard of in modern systems.
yours:
The PCjr could be purchased with full manuals that included BIOS source code and all hardware schematics. This made for the popularity of hobby/home modifications and a number of small shop hardware upgrade companies, eventually being absorbed by PC Enterprises.
my comment:
such open design is unheard of in modern systems. You can't to to Circuit City or Walmart and purchase the firmware manuals and detailed schematics of any computer system you want to own. The PCjr was meant to be a hobby system, and the release of such detail was not seen as any threat, as it was a unique system design, not a PC clone. We live in a world of open software in a battle with central corporate software. We might again see the day of open hardware. In the meantime, my comment is true, unless you want to provide examples of shrinkwrapped retail documentation of any major brand of computer.
:First of all, the PCjr tech reference was a seperate product; what you originally wrote implied that it was bundled with it. You also imply that the PCjr tech reference was significantly different from other personal computers of the time, yet the 5150 also had a full tech reference available, as did the Apple II and other personal computers. Also, the statement "Such open design is unheard of in modern systems" is ludicrous because everything you want to know about your PC, at the lowest levels, is available for free on the web. Not necessarily from the manufacturers, but from many different sources. Finally, the PCjr was not meant as a "hobby" system, it was meant as a family system -- there is a very big difference between the two.
:Full disclosure of the hardware was significant, I agree, but you need to state it like that, instead of trying to make some sort of social comment on modern computing. Wikipedia is about objective facts, not POV commentary.--Trixter 15:49, 21 August 2006 (UTC)
thread_title:  Fourth topic 

message: mine:
The two front cartridge slots were used not only for stand alone bootable programs, that didn't require an OS, they were also used with third party cartridges to update the system BIOS and other firmware. Multiple patches from various vendors were included on a single combo-cartridge slot. These were used to support add-on hardware, bypass certain limitations of design, and keep up with changing OS requirements.
yours:
The two front cartridge slots were used not only for stand alone bootable programs but also with third party cartridges to update the system BIOS and other firmware. Multiple patches from various vendors were included on a single combo-cartridge slot. These were used to support add-on hardware, bypass certain design limitations, and keep up with changing OS requirements.
my comment:
I'm guessing you think all computers run with an OS or something. This is very much not true, as people dealing withe embedded systems will tell you. In the days of the PCjr, many hacking away at eary versions of PC's, would use Disk Operating Systems { early DOS before the DOS that we came to know existed } to enable hard drive attachments. Production industrial systems would then use the tested software burned onto chips to actaully run. Please leave the comment about OS alone, so people can understant this as a computer that could run with an OS or without it, simply by slamming a game style cartridge in the front or pulling it out.
:I didn't change your content at all with my edit; I only fixed the awkward grammar! What in my edits caused you to think I was altering the informational content of what you wrote? --Trixter 16:01, 21 August 2006 (UTC)
thread_title:  Fifth topic 

message: mine:
The PCjr had wireless keyboards that could also operate with a telephone style cable. This worked well enough to allow the keyboard to be placed in front of the system to type.
yours:
The PCjr's wireless keyboards could also operate with an RJ11 telephone-style cable. This enabled the keyboard to be used like a traditional keyboard, saving the battery drain used when in wireless mode.
my comment:
The commotion about the keyboard and PCjr was huge and was so much a part of the system's termination, I want the wording very specific. It was not an RJ11, if you want to be technical and nit-pick. It had a connector on only one end like a telephone and the modulations and signals were completely not analog audio transmit/receive. My comment is to state that the wireless keyboard worked just fine in front of the computer, though morons complained when it would not work from accros the room, like a TV remote. I did not intend to comment about the battery drain in this paragraph.
:The cable used actual RJ11 jacks, and you wrote telephone-style cable, so the RJ11 edit is valid and correct. Also, if the point of your content was to make a comment on how well the wireless keyboard worked, you did not convey that in your content at all and should mention it specifically. (By the way, not working from across the room like a TV remote was indeed a valid complaint, since it was a major advertising point of the PCjr! The PCjr was marketed as being perfect to connect to the family television, like most personal computers it was competing against. Having a wireless keyboard was a major selling point for people who wanted to do this.) --Trixter 16:07, 21 August 2006 (UTC)
thread_title:  Sixth topic 

message: Trixter, you said
"No, it wouldn't, because your personal account isn't verifiable by other sources."
are there such things as verifiable accounts for people to enter stuff in wiki? — Bptdude 05:32, 26 August 2006 (UTC)
replies: text: Check Wikipedia:Verifiability. — Trixter 19:35, 31 August 2006 (UTC)
thread_title:  Verifiable accounts? 

message: i removed the citation needed comment for the line about a mouse was available that used the serial port and lightpen. trixter, was that you? i found a site called oldskooler where you yourself proclaimed knowledge about the company that made it, Mouse Systems. i actually owned one and used it for almost ten years. i'll leave it to you to have fun traking down mouse system's PCjr mice. it's really there, trust me. it required a special reflective pad that was silver colored with dark blue grid lines on it. it was very similar to the mouse i used on old solaris systems, which is why i liked it. — Bptdude 06:41, 28 September 2006 (UTC)
replies: text: The citation wasn't there to dispute the optic mouse -- I owned a Mouse Systems mouse as well. The citation needed was for the comment "The lightpen port was later used in combination with the serial port". That is the part that needs citation, since every Mouse Systems mouse I ever saw had only a serial port. Can you confirm the PCjr version also needed to use the serial port? If not, that item should be removed, or at least have the citation part put back on. --Trixter 18:41, 28 September 2006 (UTC)
replies: text: I was bored enough to try to find the reference on the web and couldn't. I did find the gentleman who invented the optical mouse, Steve Kirsh, who founded Mouse Systems and emailed him, but he wasn't much help, and didn't seem in the mood. I have a feeling Mouse Systems had an unpleasant demise. I did read a bit about Mouse Systems mice. The reason my PCjr mouse was so much like the one on the Sun workstation, is that they were both Mouse Systems mice, and bacsically the same thing. All Mouse Systems mice required an external power source. This was done on PC's by a special adapter that piggybacked into the keyboard port. I'm assuming then my Mouse Systems PCjr mouse was just using the lightpen port for power. If this is not familiar to you, how did yours work? — Bptdude 21:32, 28 September 2006 (UTC)
replies: text: I never had a PCjr one. I did some research of my own and found that the PCjr version did indeed connect to the lightpen port. However, it did so for the +5vdc power, not because of anything "optical" about it. So the citation is not needed.--Trixter 18:25, 29 September 2006 (UTC)
thread_title:  Third-party mouse using serial port and lightpen port 

message: The PCjr was a very hackable system. 3rd party developed upgrades were created to make the PCjr's enhanced video modes and TI sound chip compatable with how the Tandy 1000 computers addressed them. Another hardware hack that involved adding parts, cutting PCB traces and soldering enabled the stock IBM floppy controller to support two drives instead of one. The floppy hack and others were detailed in magazines like "Home Computer Magazine" and for PCjr owners who didn't feel up to going at their computer's insides with an X-Acto knife, wire clippers and soldering iron, several 3rd parties offered services to do the modifications. The Tandy 1000 video hack was simple, piggyback one 7400 series TTL chip on top of one on the mainboard for power, cut one trace on the top side of the mainboard and solder three or four wires from the new chip to points on the mainboard. Easy as putting a modchip in an original Playstation. I don't know what all the Tandy 1000 sound modification involved.
There was an even greater number of add-ons and upgrades that were easy to install plug-ins. The NEC V-20 CPU added a small bit of speed to DOS programs and with the 22-NICE emulator the PCjr with that CPU's native Z-80 mode could run CP/M software faster than many dedicated CP/M computers. (In my experience it was much faster than a Xeox 820-II.) There was a battery backed realtime clock which plugged in between one of the BIOS ROM chips and the mainboard, a RAM and FPU upgrade that plugged in between the CPU and mainboard, and something that plugged into the socket for the infrared keyboard reciever. I don't recall what that one was. Yet another modification was a 'thin font' module which plugged in between one of the BIOS ROM chips and the mainboard- with a remotely mounted switch it swapped between the original font and a thinner style that reduced 'blooming' of the characters on the PCjr's monitor, which used a TV style 'slot mask' CRT with large, rectangular phosphor trios. IIRC, this thin font mod was integrated into one or more of the several cartridges produced by PC Enterprises.
Those PC Enterprises cartridges came with different combinations of the hacks and upgrades that were also possible by interposing between the BIOS ROM chips and the mainboard. The 'ultimate' cartridge had them all, and was of course priced higher than the cartridges with fewer hacks. This was possible because the cartridge slots were essentially a direct connection the the BIOS ROM sockets.
Some software cartridges could be used in either slot, but some had to be used specifically in only one slot. Two cartridge programs like LOTUS 123 had them marked Left and Right.
The PCrj's monitor bears nearly as much blame for the computer's market failure as does the chicklet keyboard. By using a cheaper, television quality, CRT IBM saved money but ensured many users would get eye strain trying to focus on its blurry characters in 80 column text mode. Add that to the hardware hacks. Grafting the PCjr monitor connector onto a good CGA monitor, or building an adaptor to connect a standard CGA monitor. ISTR at least one such adaptor was sold by a 3rd party vendor.
:First of all, please sign your edits so people can follow threads and see who said what. Secondly, the monitor comments seem bogus -- it was the same quality as the 5153 (I have both). There is no significant difference in 80-column mode between both monitors, so I'm not sure what you're getting at. --Trixter 15:31, 29 November 2006 (UTC)
thread_title:  Hardware hacks 

message: Hello,
I've never edited any Wikipedia entries before, so I'm going to lay out in here some info, and hopefully get some guidance from some of you on how to determine if it's relevant, what info I need to back up these claims, and where in the article it might go.
The internal modem that was sold by IBM was actually made by Novation, the maker of the famous Apple Cat. There is a proprietary command set to command the modem. This is stated in the article, but I think it's important to state that it's made by Novation. Also, I think there might be a better way to contrast this to the Hayes compatability than how it's written right now. Check out the Novation CAT article.
This modem is a 300 baud modem. I'm going to try to find some more documentation that states exactly which modes it will do, as well as other baud rates. I think it does 110 and 150.
A feature of this modem that is one of the 'raves' of Novation's modems is it's call progress detection and reporting. It will not just tell you if a line is busy, but also tell you when the line is ringing (with one 'ringing' response per ringback tone), and when there is human speech on the other line.
And with the Cartridge BASIC there is a basic command TERM that will load a terminal emulator written in basic. This terminal emulator is written to work with the proprietary command set only.
Maybe the Novation CAT page should have a blurb about this modem too?
Rixoff 05:36, 25 August 2007 (UTC)
thread_title:  Internal modem -proposed changes

message: I re-wrote the article (sort of), in order to incorporate most of the pertinent information from the trivia section. As I said in my edit summary, I left a few items out, either due to being too trivial (books being written) or incoherant ("The PCjr was manufactured in Lewisburg, Tennessee by Teledyne. Roughly 500,000 units were shipped." - When? Was this the only manufacturing location? If not, 500,000 units shipped in total, or 500,000 shipped from Lewisburg?). Give the new version the once-over, and let me know what you think! --Badger Drink 06:16, 1 September 2007 (UTC)
thread_title:  Ding dong, the trivia is dead... 

message: The PCjr also lacked a DMA controller. Thus, the 8088 CPU had to service standard system interrupts such as the serial port or the keyboard directly. Hence, the PCjr couldn't be used with modems faster than 2400 baud, and it would refuse to process keyboard input if its buffer was full.
This paragraph is suspect. On the PC, neither the keyboard nor serial port are DMA driven or buffered in hardware and must be serviced by interrupts on a byte basis. FIFOs were not added to the serial port hardware until the introduction of the 16550 UART. Also, any computer will refuse to process keyboard input once its buffer is full!
What I suspect was meant was that keyboard or serial data could be lost during a floppy drive transfer, since DMA was used on the PC to service the FDC, and the lack of a DMA controller on the PCjr presumably meant that either interrupts had to be disabled or the CPU could not service other interrupts quickly enough. 24.4.198.162 (talk) 21:30, 17 October 2009 (UTC)
thread_title:  Keyboard and serial DMA? 

message: Why does the article keep switching to present tense? My guess is that a lot of the text was copied and pasted from another, very old, source. The style of the article even changes in these sections.--RJBowman (talk) 06:11, 17 February 2015 (UTC)
replies: text: No text has been copied from elsewhere as far as I know; certainly not within my own edits. Present tense is used when appropriate as per WP:COMPNOW. Ylee (talk) 06:14, 17 February 2015 (UTC)
thread_title:  Press-release journalism? 

message: For this to have any shot at GAN, the lead must be expanded to properly summarize the article. This is hard, but the lead is the most important part of the article. Hekerui (talk) 09:18, 20 July 2015 (UTC)
thread_title: Lead

message: In this section it states,
"In practice the PCjr proved incompatible with about 60% of PC applications including WordStar and two programs often used to test PC compatibles' compatibility, 1-2-3 and Microsoft Flight Simulator"
None of the references cited indicate that the PCjr was incompatible with Microsoft Flight Simulator. The PCjr was in fact compatible with Microsoft Flight Simulator 1.0. I played it all the time. — Preceding unsigned comment added by 167.220.151.252 (talk) 18:53, 3 December 2015 (UTC)
thread_title:  History - not fully PC compatible - Microsoft Flight Simulator 

message: In the section, "Differences from the IBM PC", it is claimed that the PCjr has a "built-in RF modulator". As I recall you need an external TV adapter to feed the video monitor signal into the antenna connection of a TV. Does this need to be corrected? — Preceding unsigned comment added by Mcsew2k (talk • contribs) 17:24, 23 September 2018 (UTC)
thread_title:  RF modulator 

message: — Assignment last updated by WKJacob (talk) 14:06, 24 August 2023 (UTC)
thread_title: Wiki Education assignment: First Year English Composition 1001