Questions tagged [commodore]

For quesitons regarding Commodore Business Machines itself or its products that do not have a more specific tag such as commodore-64 or amiga.

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112
votes
2answers
19k views

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 ...
53
votes
2answers
10k views

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 ...
47
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4answers
3k views

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 ...
40
votes
7answers
5k views

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-...
28
votes
5answers
5k views

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 ...
22
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4answers
6k views

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)...
21
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3answers
2k views

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 ...
20
votes
7answers
5k views

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, ...
19
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4answers
1k views

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 ...
19
votes
1answer
2k views

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,...
18
votes
3answers
4k views

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 ...
18
votes
2answers
2k views

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 ...
15
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4answers
731 views

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 ...
15
votes
1answer
620 views

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 ...
13
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2answers
2k views

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 ...
13
votes
1answer
868 views

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 ...
12
votes
7answers
1k views

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 ...
12
votes
1answer
4k views

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 ...
12
votes
1answer
915 views

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 ...
11
votes
4answers
952 views

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 ...
11
votes
3answers
502 views

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 ...
11
votes
2answers
901 views

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 ...
10
votes
1answer
1k views

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 ...
10
votes
1answer
539 views

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 ...
9
votes
2answers
956 views

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 ...
9
votes
4answers
831 views

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. ...
9
votes
1answer
3k views

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?
9
votes
4answers
2k views

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-...
9
votes
4answers
768 views

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 ...
9
votes
2answers
590 views

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 ...
9
votes
3answers
2k views

What is the best option to connect old computer to modern TV

I was exploring different options of connecting both my Atari ST and C64 to a modern TV. I opted for a composite signal passed through a cheap AV to VGA converter, and although the display works, ...
9
votes
2answers
1k views

Is there a device that will take composite video from a vintage computer and filter it so it is green or amber like the old monochrome monitors?

I know some monitors have a mono/green switch, but I'd like to do this with my 1702. If one doesn't exist, I'll probably try and make one (somehow).
9
votes
1answer
559 views

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, ...
9
votes
0answers
453 views

How many Amiga 3000's were produced?

While revisiting this question: Seeking details relating to Amiga 3000 serial numbers I began to wonder how many actual Amiga 3000's were produced by Commodore. I suspect (like most production ...
8
votes
3answers
1k views

How to spin up 1541 drive without C64

I have a 1541 drive and I want to make it spin but I don’t have a Commodore computer. I don’t need to read data, I would just like the drive to spin. Can I manually tell it to spin using a raspberry ...
8
votes
2answers
628 views

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),...
8
votes
3answers
770 views

Commodore 8-bit character sets

Is the character set format same on every Commodore 8-bit computer or are there any character size, character order, or other differences between the machines? I'm purely interested in the character ...
8
votes
2answers
834 views

Is it possible to bank out Kernal in Commodore PET, VIC-20 or 264 series computers?

You can bank out Kernal ROM in C64 using $01 register. This was preferred by game/demo coders who wants to employ self tuned routines and wants to expose ram 'underneath'. You can do lda #$35 : sta $...
8
votes
1answer
560 views

Why did the Commodore PET 2001 take so long to ship?

In 1976 Commodore as a company had been running for more than twenty years and had extensive experience with designining and selling consumer electronics products: they were one of the top-selling ...
8
votes
1answer
486 views

Selling computers via dealers and the mass market

As discussed in Origin of dealer networks, the two main ways to sell computers are, and particularly were in the old days, Three digit price tag sold to individuals => mass market, department stores ...
8
votes
2answers
568 views

How advanced was the Amiga Walker prototype?

The Amiga Walker was a prototype Amiga computer that never made it to market. Wikipedia has some info including a photo of a motherboard. How advanced was the prototype? Could it boot and run Amiga ...
7
votes
3answers
534 views

How do I adjust the OS print output to different screen dimensions on VIC-20?

The graphics chip of the VIC-20 has a setting for the number of columns and the number of rows to display. So, instead of the default values of 22 columns and 23 rows, for example, it is possible to ...
7
votes
2answers
735 views

What does Shift-RETURN do on Commodore's 8-bit computers?

Someone recently commented that, "a shift-Return is really different from a normal one. It moves the cursor to the next line, but does not complete an input operation." This would be interesting and ...
7
votes
1answer
388 views

Digital PCB Plans for Retro Computers

I use software like Fritzing or Autodesk EAGLE to draw my Raspberry Pi or Arduino projects and was wondering if there is a source for PCB plans of for example an Amiga 500 in a format readable for ...
7
votes
1answer
477 views

Does the Commodore 64 power switch have a history of failing?

My original (1983?) Commodore 64 (brown breadbox with grey function keys) has trouble powering on. Specifically, when I flip the power switch the power LED will glow dimly and the machine fails to ...
6
votes
4answers
671 views

What was the 2nd best selling computer ever? [closed]

It's widely known that the Commodore 64 was the best-selling single model of personal computer. Which computer make & model got second place? To clarify, I'm looking for an objective answer about ...
6
votes
2answers
519 views

Commodore monitor to VGA or HDMI

I have this monitor, which I think is a Commodore 64 monitor. I would like to connect it to a pc. Anyone know how to convert VGA or HDMI to this connector format? I've tried searching, but so far I'...
6
votes
2answers
393 views

What's the timeline of Commodore diskette drives?

Commodore produced a number of different floppy diskette drive units, both 8" and 5.25", over the course of its history. Can someone provide a chronological list of the drives, their release dates, ...
6
votes
3answers
1k views

Getting your Commodore VIC-20, 64 or 128 online

Back in the day, of course we used modems ("dial-up modems" in today's parlance) to get our Commodores connected to other systems. These days I know several people have concocted options to get ...
6
votes
3answers
558 views

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 ...