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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Seeking information regarding how/when Commodore would refurbish a disk drive

I recently added a Commodore 1581 3.5" floppy disk drive to my collection. Being interested in the history of my new toy, I wondered what I might learn from it's serial number. After some ...
Geo...'s user avatar
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Where to find datasheets for MOS (Commodore) 85xx chips?

It seems difficult to find any detailed technical information online for the 85xx chips used in later Commodore 8-bit computers. For example, there's an excellent archive at http://www.6502.org/...
Brian H's user avatar
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3 votes
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How is the Commodore BASIC RND function seeded, depending on the argument?

In AppleSoft, RND with a negative number performs a seed on the generator with that number. So, as I understand it X=RND(-1) is the equivalent of RANDOMIZE 1:X=RND(1): If aexpr is positive, returns a ...
Maury Markowitz's user avatar
5 votes
2 answers
418 views

Memory gap in Commodore PET

Most largish programs written for the Commodore PET have a bunch of rem statements somewhere around the 8K or 16K area. The normal comment is something to do with a hole in memory. I remember PET ...
cup's user avatar
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18 votes
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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 ...
Alan B's user avatar
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9 votes
1 answer
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Sending DOS commands in assembly on my C64

Consider the following Basic program for the C64. 10 OPEN 15,8,15 20 PRINT#15, "I" 30 CLOSE 15 This classic gem simply opens the 'command channel' and sends the DOS 'init' command to the ...
Geo...'s user avatar
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12 votes
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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 ...
Geo...'s user avatar
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Name of Commodore tape format?

How did Commodore call their tape format, if there ever was a specific name for it? OK, let me clarify. I would be interested in the technical term of the encoding as well as any specific name, should ...
bugjam's user avatar
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1 answer
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Correct voltages and current draw for Commodore PC-1

I am fixing a Commodore PC-1 PSU for a friend and want to know if the PSU is behaving as expected. No modern PSU suggestions (e.g. Meanwell), if you don't mind! :) Question: What are the voltage ...
Nick Bolton's user avatar
3 votes
1 answer
220 views

Converting CGA (from Commodore PC40) to RetroTink 5X?

I am quite new to the CGA world but I recently got hold on a Commodore PC40-01 desktop computer. This has a CGA card but how to connect this to my RetroTink 5X-Pro, so I can get it to be displayed on ...
Beauvais's user avatar
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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. ...
user's user avatar
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Can two single Commodore disk drives emulate a dual disk drive?

The floppy disk drives manufactured for Commodore 8-bit computers (by Commodore itself and by various third parties) are either single-drive units, or dual-drive units where two disk drives share the ...
Psychonaut's user avatar
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What are the safest temporary zero-page locations across all Commodore (CBM) machines?

I have some 6502 machine-language routines that I'd like to be as portable as possible across all, or as many as possible, Commodore 8-bit machines, including the PET (BASIC 1.0, 2.0, 4.0), VIC-20 and ...
cjs's user avatar
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Why didn't the original Commodore PET computer use a standard typewriter style keyboard?

Being a huge fan of Commodore, I've often wondered why Commodore would use such a horrible keyboard layout for their premier computer utilizing an alpha-numeric keyboard. My only guesses would be ...
Hitek's user avatar
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11 votes
1 answer
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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), ...
Psychonaut's user avatar
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26 votes
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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-...
Superfrog's user avatar
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3 answers
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Is there a version of Python that runs on a QL, Speccy or a Commodore?

Does any Python port run on any Speccies or Commodores? I am hopeful about QL, since: Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128 KB of RAM, which was officially ...
user1095108's user avatar
9 votes
2 answers
2k views

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 ...
wizofwor's user avatar
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20 votes
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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 ...
Psychonaut's user avatar
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2 votes
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Commodore 1352 mouse converter

My Commodore PC30-III can only handle a Commodore 1352 mouse, but it is practically impossible to buy one. I own a couple of Amiga and serial PC mice that if I plug in, the buttons seem to work, but ...
Peter Szanto's user avatar
12 votes
1 answer
2k views

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:
Peter Szanto's user avatar
15 votes
5 answers
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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 ...
Peter Szanto's user avatar
5 votes
1 answer
263 views

Which early computer games supported "English" from the paddle controller?

In relation to this answer about the "English" control of the Magnavox Odyssey, I am wondering if the concept found its way into other games for later computers and consoles that supported ...
Brian H's user avatar
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2 votes
2 answers
350 views

How to properly convert an active-low joystick routine to active-high

My last question wasn't specific enough so I'll rephrase it. I've been having trouble with programming game consoles/computers like Commodore 64 that have active-low joysticks, where the bits are all ...
puppydrum64's user avatar
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21 votes
3 answers
6k views

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 ...
Peter Szanto's user avatar
6 votes
1 answer
334 views

Commodore 1581 crashes during format

I have a Commodore 1581 (800k 3.5" DD) floppy drive which reads and writes data just fine (with DD disks only of course), but it crashes (drive keeps spinning forever, stops moving the head and ...
TeaRex's user avatar
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8 votes
1 answer
327 views

How was end-of-file stored on a Commodore 1541 disk? [duplicate]

On a VIC-20 or C-64, you could open a sequential file on a 1541, write exactly N bytes (say, 47 bytes) to it, then close it. Then you could open the same file for reading and start reading byte by ...
Nimloth's user avatar
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24 votes
1 answer
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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 ...
Psychonaut's user avatar
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11 votes
2 answers
980 views

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-...
Psychonaut's user avatar
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6 votes
1 answer
761 views

Why does the VICE "load" command skip the first two bytes?

I am studying assembly of the C64, and of course using VICE to do so. VICE has the load command to load data straight into the C64 RAM. I reckoned I could use that to put machine code into RAM and run ...
Bart Friederichs's user avatar
23 votes
8 answers
4k views

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 ...
AvaTaylor's user avatar
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16 votes
3 answers
2k views

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 ...
TopCat's user avatar
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4 votes
2 answers
250 views

Amiga 500 WorkBench 1.2 Freezes

When I load the Workbench, it loads normally and I can use the mouse to select and open folders and load programs as expected. What happens is, at random, if I double-click on an icon the icon will ...
Raymond Livezey's user avatar
11 votes
4 answers
1k views

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 ...
scruss's user avatar
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6 votes
1 answer
141 views

How can I restore the VDC RAM to usable text mode after clearing memory for hi-res graphics?

So, I've got a C-128 with only 16K of VDC video RAM. I've finished my lovely high-resolution graphics routine on the RGBI display and want to exit to BASIC with a functional 80-column text screen, ...
Mark Reed's user avatar
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12 votes
4 answers
1k views

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....
rwallace's user avatar
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2 votes
3 answers
327 views

Commodore C386SX-LT, what is causing this hissing sound

I'm trying to work out what is wrong with this laptop. There is a hissing sound coming from the power board mid left. The laptop screen remains off and there is no output to external VGA unless it ...
Bartek Malysz's user avatar
4 votes
1 answer
338 views

From what errors could Commodore's tape loader recover

The Commodore PET/VIC-20/C64 tape routines write out the leader for each file twice, and then write the data twice. While it would seem that this should allow data to be loaded more reliably, ...
supercat's user avatar
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7 votes
5 answers
1k views

What can be done with a USR file on the Commodore 1541 disk drive?

The USR filetype on the Commodore VC 1541 disk drive is a less common sequential file that according to some book sources can be executed as a program directly on the drive. The drive has its own 6502 ...
Peter B.'s user avatar
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7 votes
1 answer
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Could a double-sided Commodore disk be written to be used as a "flippy" on a 1541, without requiring flipping on a 1571?

Although the 1571 is capable of reading and writing both sides of a disk, accesses to the second side using the second head will be performed with the drive spinning in opposite direction from how it ...
supercat's user avatar
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10 votes
1 answer
983 views

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?
Bartek Malysz's user avatar
28 votes
1 answer
3k 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,...
Graham Lee's user avatar
14 votes
1 answer
5k 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 ...
Daeron Guiffre's user avatar
5 votes
1 answer
353 views

Why are the CBM control codes for color setting so spread out?

The control codes (my C64 handbook actually calls them ASCII codes) for color changing on the Commodore 64 are as follows: Color Control Code Color number BLACK $90 0 ...
Peter B.'s user avatar
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5 votes
2 answers
495 views

Commodore Plus/4 jiffy clock tied to screen refresh frequency? (warning: flashing images)

Warning: There are flashing images below, do not scroll down if you are sensitive to them! According to various sources (for example this for the Plus/4), both the C64 and Plus/4 have a "jiffy&...
Zoltan's user avatar
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5 votes
1 answer
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How to get GOTEK to work with CDTV?

I'm trying to connect Gotek drive to my CDTV using external caddy (amitek). The drive has 3 digit LED display, after boot i can see F-F. When I insert Flash drive it detects images on it, I can ...
Bartek Malysz's user avatar
6 votes
2 answers
2k views

Is solder-on memory upgrade an option here and how to check it

I have this system with 2MB onboard RAM, but I noticed there are additional soldering pads to the right from memory chips (NEC 424400-80L, but there are also TOSHIBAs TC511664JL-10 on daughter board ...
Bartek Malysz's user avatar
3 votes
1 answer
707 views

Is this real Commodore C386SX-LT

Is the model shown on pictures an authentic Commodore C386SX-LT? Why does it look different to other photos on the Internet (some additional grey keys? above keyboard): http://www.spacereh.de/hc/com/...
Bartek Malysz's user avatar
8 votes
2 answers
844 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 ...
cjs's user avatar
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8 votes
2 answers
1k 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 ...
cjs's user avatar
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