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25th Anniversary of the IBM PCjr

Trixter said:
Actually, I wrote that with you very much in mind -- I'd love to know what parts you disagree with. If opinion, I'm curious :) and if factual, I have no problem correcting the post. Let me know.
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Nothing I would correct. Just slightly different ways of looking at things.

Sidecars were ugly. But a lot of what was needed to make a machine was already built in. A fully configured machine had an internal modem, floppy drive, 2nd serial port, 2 joystick ports, CGA+ color graphics, enhanced sound, and 128K. (If the machine had a parallel port and another 128K of memory on board it would have been a much better machine out of the gate.)

DMA capability was overrated. The number of times I had to stop typing while the diskette drive was running was minimal. Annoying at times, but not a serious design flaw. Now if you want to pick on a real design flaw, go for the keyboard using the NMI to deserialize the incoming data stream. That little flaw effectively limits the machine to around 2400 bps for serial communications.

Technical correction - the PCjr monitor could be used on the PC Convertible. I nearly fell over when somebody showed me a PC Convertible monitor, claiming it was a PCjr monitor. (They were PCjr owners and saw the Berg connector on the monitor.)

The 'Chiclet' keyboard was replaced for free by a slightly better keyboard within the first few months of the machine's life. The keyboard issue is overblown when you take this into account. If you contacted IBM, you got the new keyboard - no questions asked. The new keyboard is internally the same as the original keyboard, including the rubber dome technology. The major difference is the shape of the keycaps, which more people are used to for touch typing - bigger with angled sides is better than small and rectangular.

Criticizing the machine for rebooting when a cartridge was inserted or removed is a little unfair. How many other machines of the time do you know let you hot-swap a ROM upgrade without powering down? Living through a machine reset is minor for what it allows you to do. And besides delivering software, those cartridges allowed for system ROM enhancements which were unheard of on other PCs.

Lastly, I took the liberty of posting a comment on the blog about the upgrade/hack culture that grew up around the PCjr because of these shortcomings. No other IBM machine (with the exception of the 6Mhz PC AT that was often bumped to 8Mhz) was ever so widely modified by owners.
 
mbbrutman said:
Now if you want to pick on a real design flaw, go for the keyboard using the NMI to deserialize the incoming data stream. That little flaw effectively limits the machine to around 2400 bps for serial communications.
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2400bps interactive communications, yes :)

What's odd about the NMI is that, looking at the tech ref, it can be masked off. So I guess it really is an "MI" and not an NMI.

The 'Chiclet' keyboard was replaced for free by a slightly better keyboard within the first few months of the machine's life. The keyboard issue is overblown when you take this into account. If you contacted IBM, you got the new keyboard - no questions asked. The new keyboard is internally the same as the original keyboard, including the rubber dome technology. The major difference is the shape of the keycaps, which more people are used to for touch typing - bigger with angled sides is better than small and rectangular.
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I was intentionally being somewhat sensationalist when I wrote that, but I agree that I should have mentioned a free upgrade was available. I've added a note to that effect.

Criticizing the machine for rebooting when a cartridge was inserted or removed is a little unfair. How many other machines of the time do you know let you hot-swap a ROM upgrade without powering down? Living through a machine reset is minor for what it allows you to do. And besides delivering software, those cartridges allowed for system ROM enhancements which were unheard of on other PCs.
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I wasn't really criticizing it for that, just mentioning it as a quirk. I put it in the wrong section, so I've rearranged it to the "quirk" column.

Lastly, I took the liberty of posting a comment on the blog about the upgrade/hack culture that grew up around the PCjr because of these shortcomings. No other IBM machine (with the exception of the 6Mhz PC AT that was often bumped to 8Mhz) was ever so widely modified by owners.
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Agreed :)
 
Having had a recent epiphany, I feel a sacred obligation to preach the gospel as it was revealed to me (through a post in these forums). For many years I had unfairly judged the Peanut as an inferior machine because, like many other folks, I was intent on comparing it to the IBM PC. The only fair comparison, however, is vs other 'Home Computers' of the era, the market it was designed to compete in, and in that light, the PCjr outshines all others in it's class.

--T
 
Terry Yager said:
Having had a recent epiphany, I feel a sacred obligation to preach the gospel as it was revealed to me (through a post in these forums). For many years I had unfairly judged the Peanut as an inferior machine because, like many other folks, I was intent on comparing it to the IBM PC. The only fair comparison, however, is vs other 'Home Computers' of the era, the market it was designed to compete in, and in that light, the PCjr outshines all others in it's class.

--T
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I have a fondness for the PCjr, but I think it's something of an exaggeration to say it outshined everything else in its class. Maybe if it were half the price it was released at I would agree, but it's arguable whether it was that much of an improvement over the Commodore 64 or Atari 8-bit, which were far cheaper and better supported. You can certainly say price-wise the Apple IIe was in its class and it certainly had better graphics and sound, particularly in non-CGA/PC speaker software cases, but it's still not an all-out slaughter. Certainly in the case of the Tandy 1000 we can see the jr's full potential realized, but even then it's not a huge jump over the aforementioned systems save for things like memory (and let's remember that Tandy dropped the cartridge ports).
 
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