Questions tagged [commodore]
Commodore Business Machines and their products. Use more specific tags like [commodore-64] or [amiga] instead if appropriate.
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How did Commodore's anti-Microsoft Easter Egg work?
A couple years ago the Toronto PET Users Group published an article (The Great Commodore/Microsoft Easter Egg War, on p. 7) about a newly discovered anti-Microsoft Easter Egg that Commodore hid in the ...
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Why did Commodore fill their power supplies with epoxy?
If you know anything about the Commodore 64 (and other Commodores, really) you know that Commodore really went the cheap route and produced some awful power supplies. The Commodore 128 PSU isn't ...
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Why does the Commodore C128 perform poorly when running CP/M?
I have seen several claims of poor performance of the C128 when running CP/M, and would like to better understand these claims, especially in comparison to other CP/M machines of the early to mid-...
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What precautions to take when powering on old computer for the first time in years
I have a Commodore 128D that hasn't been powered in about 15 years. I want to begin using it again. It has been stored in cool dry places like attached garages, in a cardboard box.
I hope this ...
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Why did Commodore sell CPUs to its competitors?
Many of the most popular personal computers and video game consoles of the 1970s and 1980s, including those made by Commodore, Apple, and Atari, used the 6502 CPU (or some close relative, such as the ...
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Who ended up owning Commodore's semiconductor IP?
The question of ownership of Amiga-related intellectual property post-Commodore is famously difficult to answer. My question is: does anyone "own" Commodore's semiconductor IP now, and if so,...
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Why was IBM BASIC so Huge?
The early versions of Microsoft BASIC required 4KB of ROM, and many versions existed in the 8KB and 16KB size. But Microsoft's IBM BASIC (known as "Cassette BASIC") for the original IBM PC (Model 5150)...
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Why did the stock Amigas not have a battery for keeping the time/date?
The Amiga computers were advanced machines meant to do all sorts of things, including file management. They had a GUI OS (Workbench) and everything right from the very start. They were not some games-...
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Why was it not possible to cost-reduce the Amiga 500?
According to 'Commodore: The Final Years' (whole trilogy highly recommended, BTW), page 129, 'Jeff Porter realized it would not be possible to significantly cost reduce the Amiga 500 to get it into ...
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How did Commodore drives produce program listings from disk directories?
CBM BASIC 2.0 has no built-in command for listing the contents of a floppy disk. Instead, the usual way is to LOAD a pseudo-file named $ from the disk into memory. The file can then be LISTed like a ...
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Why did the VIC-20 and C64 have only 22 and 40 columns when the earlier PET had 80 column text?
When I was a kid, the "real" computers in movies looked so cool with that 80-column monochrome green text.
My first computer was a VIC-20 and it always felt very "toy-like" to me ...
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Are pixels on the Commodore 64 square?
Are "tile pixels" the same size as "sprite pixels", and are they both square (ignoring the rule that multicolor sprites can only be colored in groups of two pixels)?
By "square" I mean that the ...
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Commodore BASIC and binary floating point precision
I am mildly curious that though the 6502 provides BCD arithmetic which would be useful for implementing decimal floating point, Commodore BASIC uses, like all (?) Micro-Soft BASIC, binary floating ...
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Why doesn’t my VGA-to-HDMI converter work with my 286 PC?
I have a Commodore PC 30-III with a Cirrus ISA VGA card in it.
I wanted to connect to an HDMI display by using a mini VGA-to-HDMI converter
The converter doesn't generate any output. The machine ...
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Which 8-bit computers were used in German schools in the 1980s?
In the 1980s, each country had a particular brand of computer that was most commonly used in schools; often, there was pressure to go with a local manufacturer. In the US, the Apple II. In Britain, ...
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Can powering on/off a 1541 damage a disk left inside?
The User's Guide for the Commodore 1541 disk drive includes a vague warning, on page 7, to "remember to always remove the diskette before the drive is turned off or on". Some third-party ...
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What was the role of Commodore-West Germany?
Most of the history of Commodore in personal computers took place while East and West Germany were divided, and Commodore maintained a significant corporate presence in West Germany. While I believe ...
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Is there software that will run across multiple Commodore 8-bit machines without modification?
I noticed in some of the answers in this question that the Commodore 8-bit line apparently used a jump table at $03xx for entry into the kernel ("kernal" for the pedantic) routines. Figuring that the ...
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Where are the blueprints of MOS chips?
Atari historians have been able to find documents and tapes of chips and hardware developed at Atari. E.g. http://atariage.com/forums/topic/154479-new-gtia-chips/ .
Nothing like this is happening for ...
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Commodore 64 - any way to safely plug in a cartridge when the power is on?
Back in the early 1980s when my friends and I all had Commodore 64s, we all knew never to plug a cartridge in with the power on.
I once got a tape from someone with lots of utility programmes, one of ...
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What was the release date of the MOS 8502?
I have been unable to find when the MOS 8502 was first released to customers. The process it was made on was available from 1979, but MOS don't appear to have used it for their own parts at that time.
...
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VIC20, VIC-20, or VIC 20?
The 'tag' on this website calls it 'VIC-20', but the VIC20 user manual (Personal Computing on the VIC20) http://cini.classiccmp.org/pdf/Commodore/VIC-20%20User's%20Manual.pdf calls the VIC either ...
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What is the difference between the Commodore 1701 and the 1702?
Among the monitors offered by Commodore were the 1701 and the 1702, which, to my recollection, looked pretty much identical. Were there any cosmetic, functional, or other differences between the two?
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Amiga floppy disks and GCR vs MFM
According to the Wikipedia article on GCR, the Commodore 1541 disk drive used a particularly efficient GCR encoding scheme to cram 170K onto the same 5.25" disks that in an Apple drive only ...
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Commodore Mouse not recognized by a Commodore PC30-III 286 machine
I have Commodore PC 30-III 286 machine with a serial port at the back labelled "mouse". If I plug my Commodore mouse 1900 serial mouse then execute mouse.com at the DOS prompt then I get the ...
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Does the Commodore CDTV-CR contain a 65C02 for some reason?
Browsing around the FS-UAE source code I discovered a 65(S)C02 emulation core, which appears to not be referenced anywhere outside of some CDTV-CR related source file.
Apparently, a CDTV is ...
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Part-bad chips other than RAM
In the early eighties, you could buy half-bad 64k RAM chips at a discount. Some cost-conscious manufacturers such as Sinclair and Tandy took advantage of this, buying eight such chips to make a 32K ...
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Who were the Atari ST designers pilfered from Commodore?
After Jack Tramiel was fired from Commodore and became the owner of Atari, I believe he offered jobs to a number of key technical people who followed him from Commodore. Who were the key people (if ...
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Is this an Amiga? If so, which model?
In the 1998 Swedish comedy musical "Åke från Åstol", there's a moment toward the end when a man is pushing around some sort of Amiga-looking computer with a monitor and mouse on a ...
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What is this unusual syntax for the Commodore SYS command?
I was recently interested in how to 'bload' some data on my commodore 64. For the sake of discussion the data isn't really relevant (it could be any blob of bytes).
Generally you can load a file into ...
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Did the Commodore datasette interface provide greater reliability?
Cassette, being cheaper than a floppy disk drive, was a popular storage medium in the 8-bit era. Some computers such as the Sinclair Spectrum, just provided a port to plug in an existing cassette deck....
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How can I enter BIOS setup on a Commodore PC 30-III?
I have a Commodore PC 30-III but I can't find a way to start the BIOS menu. It displays the following message during startup:
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How do you send code to a Commodore disk drive and run it?
Commodore disk drives such as the 1541 used with the Commodore 64 and similar computers, and the earlier 8050 used with the PET series, had their own 6502 CPU and 2 kB or so of RAM used to run the ...
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What is the proper way to test the PSU output for a Commodore 128D?
This question is directly related to comments on the more general question and answer here.
The Commodore 128D and 128D-CR have an internal PSU that can be readily and safely disconnected from the ...
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Commodore BASIC: why was the PET's GOTO so slow?
Received wisdom has it that Commodore didn't want to pay Microsoft extra for updated BASIC interpreters, and thus very little changed in Commodore BASIC v2 from the PETs to the C64. But consider the ...
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How was "GEOS" meant to be pronounced?
GEOS was a hugely popular operating environment for 8-bit Commodore and Apple machines. It was developed and published by Berkeley Softworks, who eventually released a 16-bit version for IBM-...
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Commodore 64 with partly working keyboard (part 2)
I have a C64 that has recently stopped responding to two 'columns' of keys, namely '9,0' 'i,o' 'j,k' and 'n,m' - I've swapped the CIA chips (U1 and U2) to no effect, so I pulled a keyboard from a ...
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Did all integrated Commodore PET monitors always use 60 Hz refresh?
All models of the Commodore PET line had built-in monitors, and at least the U.S. models had 60 Hz refresh. For the European models there was no need for compatibility with European television ...
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Why was Paperback Writer renamed to Pocket Writer?
I was a big fan of Digital Solutions Inc.'s Paperback Software, a Commodore 64/128 productivity suite that featured an interoperable word processor (Paperback Writer), spreadsheet (Paperback Planner), ...
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Possible cause for C128 A/V output containing faintly coloured columns and failing shortly after?
I recently acquired a Commodore 128. It worked fine for about an hour, in both C64 and C128 mode, at the exception of some coloured bars, before displaying garbage and not booting anymore into any ...
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Did any devices use the Commodore 64 joystick ports as outputs or two-way communications ports?
Looking at the schematic and explanation of how the C64 joystick
ports work, it seems clear that the stick direction and button
lines (JOYA0, through JOYA3 for port 1 and JOYB0, through
JOYB3 for port ...
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Is it possible to boot C64/C128 from floppy
When powered on 1541 reads the disk for a brief moment. Is it used to boot system from floppy? Is it possible to create a bootable commodore 64 floppy?
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Commodore Plus/4 60671 bytes free - how?
It is widely known that, while the Commodore 64 did indeed provide 64K of RAM for machine code programs, only 38K was usable from BASIC; this was because bank switching was needed to get at the rest, ...
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What is this extra lead in my monitor cable?
I have a breadbox Commodore 64 with a Commodore 1702 monitor.
My monitor has three RCA-style inputs on the back:
Audio (White)
Luma (Yellow)
Chroma (Red)
I purchased a cable which claims to be an ...
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What is an "unused" memory address?
Reading this page on Commodore 64 memory structure and usage I stumbled across a cell where the table claims that this memory is unused. What exactly does this entail?
Does this mean that if you ...
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Early BASIC memory management
Can anyone verify or correct my memory here?
Long ago, I had access to a Commodore PET which I think had 8kB of memory. Also slightly less long ago, I had a Commodore 64 with its "elephatine" 64kB. ...
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Why did Commodore files not include metadata to say where in memory to load it?
On the Commodore 64, (and I believe also the VIC-20, PETs etc.) you may instruct BASIC to
LOAD "something",8
to load a file to the start of BASIC's area (and that address may vary between machines),...
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Were external floppy drives for Atari ST and Amiga inter-compatible?
Were external floppy drives for Atari ST and Amiga inter-compatible?
For example, Commodore 1541* had its own serial bus protocol. But what about the external 3.5" DD floppy disk drive on 23pins D-...
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How is PETSCII used by assembly-language programs?
First, a bit of context. I wrote an
interactive disassembler for 6502 code that,
among other things, attempts to identify ASCII strings automatically.
Appropriate source code for different assemblers ...
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Did Commodore ever produce gray colored Commodore 64?
The Commodore 64 was produced for a 12 years from 1982 to 1994. It had several iterations of case color, keyboard color & keyboard labels, badge etc.
Commodore was famous for using whatever parts ...
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