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gliptitude

Testing Tape Drive and More

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I have a C64 that I've had for a long time and never done much with, for a number of reasons.

 

I'm recently messing around with it, after failing to sell it and deciding I value it more than any potential buyers I've encountered.

 

I've only ever had one cartridge program, Music Machine. I have a disk drive and tape drive but no disks or tapes. Just yesterday, after more than 10 years owning this stuff, I hooked up the two drives for the first time and verified they power on. (I also copied some type-in graphics demos for the first time and am looking for more of those, and type-in games with graphics.)

 

Now I have an inexpensive and interesting looking disk in the mail from ebay and I am trying to figure out a cassette for the cassette drive, but they seem to be pretty expensive. And then I am reading that many of them are damaged and not necessarily playable?

 

I also thought many old cassette programs would exist as audio files online which could be played back and recorded to a new tape, but now I'm less sure that any old audio tape will work for recording and less sure that these files are exchanged online. I have no experience of the C64 scene past or present, but I remember hearing of a sprawling demo scene and I figured much of this would be distributed freely as audio files. .. Is this not the case?

 

Can I get some advice on the cassette drive? Is it worth testing out?

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I haven't heard about tape games would be more unreliable. If anything, magnetic media stored on tape is supposed to last longer (!) than magnetic media stored on disk. Also I don't know where in the world you are located, but budget tape games in Europe don't run many pounds if you want originals. There also is an increased demand for blank tapes, though I don't know what that does to the market of NOS tapes or newly manufactured ones.

 

When it comes to files online, most is archived as D64 (image of a floppy drive) or T64 (synthetic emulator format mimicing a tape). Sometimes you might find TAP files which are low level representations of tapes, which can be converted to sound by something like Audiotap or similar software. That means you may not find ready made WAV files as those are unnecessarily large and few have use of them. The demo scene e.g. at csdb.dk by the way would be entirely disk based AFAIK.

 

Up until a year ago, a C2N had the market value of $2 - $5 but I've noticed something has happened. Basically the entire collectors community is going crazy for anything retro, so even those tape recorders which otherwise are found everywhere (at least in Europe - not so much in America) suddenly have a significant value.

Edited by carlsson
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Thanks that clears things up mostly.

 

I'm in the U.S. I don't think C64 was as popular here. I only knew one kid who had one and his parents were British. We had an Atari 400/800, then Apple. Other people had IBM. All I cared about was the NES when that took off.

 

I paid $8 for a disk game title that actually interested me, including shipping from a U.S. seller. The cheapest price+shipping cassette on eBay is $18 for Sub Hunt from the U.K. I'd pay that for a game of my choosing and a tape tested to work, but most games are more than that.

 

.. I'm still looking for confirmation though, can an ordinary audio cassette make an ordinary audio recording of an ordinary audio playback of a C64 cassette program, and result in a duplicate that will load on my C64?

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I'm in the U.S. I don't think C64 was as popular here. I only knew one kid who had one and his parents were British. We had an Atari 400/800, then Apple. Other people had IBM. All I cared about was the NES when that took off.

 

The C64 was very popular in the US (and Canada). Granted, most North American users had disk drives not cassette drives. As a result, cassette based software is not as common in North America. In Europe, disk drives were very expensive so cassette based software was more common.

 

Any regular audio tape will work with a C64 tape drive. Chrome and metal tapes are not recommended. In theory, you could record an audio file of a C64 program using a standard cassette deck and the software that carlsson mentioned above. In practice, the file may not load unless you have the sound levels just right. I volunteered for a large Commodore user group back in the day. They had a special cassette desk for duplicating tapes of public domain software. I was told that the deck was modified to eliminate high frequencies and use a very specific volume level.

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Yes, if you get a good TAP which you converto WAV and playback to record onto a regular audio cassette, it should work. You may have to tweak the azimuth angle of the read head, the small screw that usually is exposed right below the lid on the C2N. If required, use a screwdriver with very small changes in either direction. You may also want to make sure the PC has its volume boosted when you record the signals. Sometimes you mind find that you need to invert the WAV to work, but the Audiotap program should have instructions on that.

 

I checked eBay. The lowest I can find is 1 GBP + shipping 4 GBP (total $6.64) if you can wait for an auction. Usually you wouldn't get overbid on those tapes. If you need it sooner, you can get the same game for 0.99 GBP + shipping 6 GBP (total $9.29). Otherwise you can find a loose tape (no box) for 2 GBP + shipping 2 GBP (total $5.31). The key is to set Item Location to Worldwide instead of Default. Of course most of those are listed as untested, so if you really need one where the seller recently loaded the tape, they'll probably charge premium for that...

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Hmm.

 

So perhaps the main advantage of tapes and the tape drive is that tapes continue to exist. Maybe I can save the type-in BASIC demos to a tape after I type them in?

 

Were some, most or any C64 demos produced by typing in BASIC programs on a consumer C64 and writing it to disk/tape?

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Thanks for checking eBay carlsson. Maybe my search was skewed to Buy it Now or maybe international results are displayed in limited selection.

 

I'd read mention elsewhere of calibrating the tape drive, which seems intimidating, and more than I'm ready for without knowing if it works.

 

.. Even simpler than digital file playback, and the issues of levels, recording quality and playback etc, I was wondering about maybe a dual tape deck from an old stereo, or another straight audio tape to audio tape recording using only audio equipment and no computers, possibly units which have no level adjustments and are just set at moderate levels.

 

I guess I imagined this was part of why the tape drive existed, because the format was cheap and ubiquitous and maybe even encouraging kid programmers to make mix tapes like people made with music, and dubbing them with consumer stereos.

 

I played around with a PXL 2000 camera from a friend's parents' basement, years after it was a competitive product and I was amazed at the time recording video to a normal audio tape. I never tried dubbing footage.

 

I guess you could have any type of record and playback heads writting any sort of tracks however that system was engineered to, and that just because they use the same size tape doesn't mean something written on one system could be read on another. But another vague C64 artifact in my head is a Nintendo DS game which had an audio file save feature for user designed levels to be shared between consoles by literally playing back the audio on one console with the speaker held next to the microphone on another DS console. It sounded like modem noises and I thought the manual or the reviews I read called it a reference to old school something or other, C64 I thought I remembered.. and it made me think that's all the tape format was, and that manual audio playback/recording was part of the process.

Edited by gliptitude

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Maybe I can save the type-in BASIC demos to a tape after I type them in?

 

Were some, most or any C64 demos produced by typing in BASIC programs on a consumer C64 and writing it to disk/tape?

 

Yes, you can definitely save your own BASIC programs to tape and load them back. It didn't occur to me that you'd have some sort of blank tapes at hand, and you just wanted to test that it is working.

 

Regarding demos, it depends what you mean. For instance Commodore supplied some demonstration programs on the 1541 Test/Demo disk, and I think similar programs were available on tape. You could also type in various programs, demos or games.

 

However for the modern demo scene (1986 and onwards), machine code is pretty much the only choice for speed and ability to control the VIC-II and SID chips fast enough. There are single part demos that could be loaded from tape, but when it comes to multi-part loading demos, also known as trackmos, it more or less is exclusively disk based both for speed and precision.

 

When it comes to "mix tapes", my personal experience is that dual tape decks degrade the sound so much that you are likely to get ?LOAD ERROR from such "hard" copies. Some decks may be more hi-fi than others and makes it work. Usually you would borrow a tape, load one file from it, put in your own tape, save the file, put back the original one, load the next etc. That way you wouldn't have to suffer from audio degrading, though of course a slower process. Sometimes you came across a game you already had, and could then load the next one.

 

For the C64, programs like Turbo Tape 64 and variations thereof (Turbo 202, Turbo 250 etc) were very popular. Those record data in a compressed format up to 10 times faster than the built in loader, so you could store more programs on each tape and still with a very high grade of reliability. Eventually the commercial publishers started implementing their own fast loaders too, sometimes using the same protocol as Turbo Tape 64 but usually coming up with their own, slightly slower versions to ensure even higher reliability and to avoid being directly compatible with what the pirates used.

 

In order to confuse you further, some artists experimented with including data tracks on their albums, usually recorded as the last track on the vinyl, possibly with spacing so the pickup normally wouldn't reach there. Pete Shelley in the UK was one of those artists, also Thompson Twins and others. However it is rather cumbersome to have your record player connected to your computer - in particular in the case of the C64 which uses a custom tape recorder, so it meant first you had to record the data from the vinyl to a blank tape, and then load the tape as normal. Yes, it was more of a gimmick than a practical way of distribute games.

 

Over here in Europe there also were some radio broadcasts with computer programs. In the Netherlands they had something called Basicode which was somewhat big. It consisted of an interpreter program in versions for various computers - Sinclair, Commodore & others - and then applications written for Basicode which somehow were possible to load back on any brand of computer. The language/environment may have been restrictive to the lowest common denominator but in principle it allowed users of different computers to share programs or data files. Other radio broadcasts were more straightforward, broadcasting a program for one computer at a time. Due to limited air time, those programs must not be very long and many remember the audio broadcasts to be unreliable, in particular if you had a moped or some other vehicle going outside, disturbing the FM broadcast.

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Excellent information thank you.

 

.. Next I'll have to learn how writing to tape works.

 

And after that, search for the best type-in games. I'll be looking for games with graphics. So far I only have graphics demos and games without graphics. I think I've identified a few and the books they are published in, but haven't found the actual code to copy yet. .. It does actually surprise me that the type-in stuff seems to exclusively be educational programs from the 80's. I would think there would be some scene reprisal of that format, testing the limits or showing off what's possible.

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The tape recorder is as easy as you ever can imagine: LOAD to load programs, SAVE to save programs. Optionally you can define device number, though it is not required.

 

LOAD"",1,1 would be the ultimate syntax: load from tape recorder into the memory location it once was saved (usually automatic unless you load machine code routines or graphics into arbitrary positions)

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While not directly related to this conversation, I'd like to mention some trivia about the Commodore tape format.

 

When a program is saved to tape, it is automatically saved twice - one copy after the other. When a program is loaded, the first copy is read into memory. The second copy is then read and compared to the first copy in memory. If the two don't agree then the computer will display the dreaded ?LOAD ERROR.

 

Having two copies slowed down the load and save process by 50%. On the plus side, there was a built in "verification" that would help to prevent a program that didn't load correctly from running.

 

Back in the day we used to use the double save trick to our advantage. We would note how long a program normally took to load. On subsequent loads we could stop the load process just past the half way mark - resulting in faster load times. This trick only worked with pure machine language programs. BASIC programs didn't set the end of memory flag until the end of the verification - so programs stopped at the halfway point wouldn't run.

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Yes, I think the second copy is one of the things Turbo Tape eliminated, plus of course shorter pulses for a total of up to tenfold faster loading times. I would assume some form of checksums would be enough to tell if a program loaded OK, as other systems can report load errors without storing the program twice as far as I know.

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.. Is there a way to page through my program after I have typed in more than fits in a single screen? I can only figure out how to move the cursor around the screen, but not go backwards to the beginning of the program.

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You use the LIST command to select which lines to list:

 

LIST without arguments gives you the entire program, use CTRL to slow it down or RUN/STOP to break

LIST 10 only lists that line

LIST 10-30 lists all lines inclusive in the range

LIST -30 lists all lines from the start to that line

LIST 30- lists all lines starting from line 30 to the end

 

So list the entire program first, try to figure out where you need to edit, then list it again but only the required lines so you can edit them and press RETURN to store the line.

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Ah okay, thank you.

 

There are a lot of type-in games here:

 

http://www.c64music.co.uk/books/

 

They are distributed as cassette files and not text or visible pages of the book. But I was able to load on an emulator and LIST, but they were many screens in length. Now I'll be able to partial LIST and copy them.

 

I have keyed in an "automatic proofreader" that is recommended in a book I found, but it doesn't proofread itself. I saved it to tape and then tried loading it and got an error. I can't remember if I tried LIST on that or not but the error said "FINAL LINE" and I had a photo I took of the program before I saved it and my final line looks correct.

 

There was a symbol in that program " { " and " } " that I couldn't find on the Commodore keyboard so I used " [ " and " ] " instead. Does that sound right?

 

There were also strange symbols I noticed when the longer game programs were listing, like highlighted letters.

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The mention of automatic proofreader and curly braces makes me think you came across listings from the COMPUTE! magazine or possibly its Gazette specialized on Commodore. In those cases, the curly braces were used to indicate special symbols, e.g. {BLK} to press Ctrl-1 and insert the symbol for changing to black text, or {4 CRSR DOWN} which means you should press the cursor down key four times etc. There usually is a guide in the magazine telling you what all those codes are supposed to mean, and you should not type them in as they are.

 

You might be interested in a command line tool called petcat which comes with VICE. It is a little tricky to get the syntax right, but is used to detokenize or tokenize BASIC programs, i.e. convert from PRG to pure text. It would allow you to print listings to paper if required.

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Yes it is an online version of a Compute! book of C64 programs in BASIC I think.

 

I don't know what VICE is.

 

Maybe I'd be better just copying the listed games from the emulator, since it is directly demonstrated and not translated or shorthanded, identical margins etc. Although they are very long and I had gotten used to the idea of having an automatic proofreader working for me.

 

It would be cool to print a program on paper after keying it in, and would help justify the continued existence of this Vic-20 printer I've had with this setup. I'll have to find some paper.

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VICE is one of the emulator packages, the other might be e.g. CCS64 or MAME depending on which one you're using.

 

One of the issues with printing graphics and control characters as they're displayed on screen is that sometimes it can be hard to tell what is what and how many, which is why even listings printed on a Commodore printer sometimes would be converted as (4 SHIFT-T) or something like that.

 

I understand that you really want to type in things to learn from the basics, but what happened with the tape recorder, did you find out if it works with a blank tape? If you need more modern, better storage solutions we're here for you to give advice.

Edited by carlsson

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Well I did finally successfully type in, save and load from a cassette. I saved a very short graphics demo and the automatic proofreader.

 

It took four tries. Each failed attempt yeilded a program with visible errors when I loaded and listed.

 

The first one honestly I was (and am) skeptical I could have made the mistakes that the recording indicated, with several whole and consecutive lines missing. That was the proofreader.

 

After that I switched to a graphics demo because it was very short and I could take a photo of the whole program on the screen exactly as entered by me. That one listed a single character entered incorrectly and my photo confirmed it.

 

After that I tried editing the program listed from the recording and re-saving it, which did not work. The new recording had the same error, (which makes me wonder how any saved program can be revised if even this single screen one wasn't).

 

Then I gave the graphics demo a third try, this time starting over, and it worked. After that I very carefully re-entered the automatic proofreader, (from scratch because I don't understand how to edit) and it worked too.

 

... But now, today .. I can't get the computer to power on!

 

I've tried several times and left it on longer than I've ever had to before, so long I was afraid to leave it on any longer. The power LED indicator lights dimly, like had been happening recently when the computer was cold, but never boots up.

 

RE my original goal of selling this computer, this has been an incredible fail. Besides having no takers at my consistently reasonable asking price on local craigslist I've actually had some pretty negative interactions with hagglers. Then the floppy disk game I ordered off eBay over two weeks ago still hasn't arrived and is apparently stuck in the U.S. Postal system. And would you believe now I am browsing eBay for another Commodore computer to replace this one!?!?

Edited by gliptitude
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Oh dear, it sounds like you'll join the camp of some of the other recent threads here about troubleshooting. While I don't think anyone directly told you so, the original PSU with the C64 is known to be a hazard as it suddenly can go bad and output too high voltages, in particular if it has suffered some physical hit at some point in time. However if you're just playing around with it while waiting for a buyer, you probably don't want to spend lots of money on replacement parts?

 

I suppose this is an old breadbin, dark grey model? If so, there is a chip called PLA that does memory handling. It goes hot and can also break suddenly, resulting in the computer not powering up. It can also be replaced, though from a recent discussion here it is not always the fault, so you could be in for a long ride if you're trying to fix something that just broke. :-(

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Hey the diskette I bought over two weeks ago just showed up. So I set the computer back up to see if it might start powering on again. After over 30 minutes it actually has.

 

I found online the commands for loading a disk program:

 

LOAD"program name",8

 

Or if you don't know the name:

 

LOAD"$",8

 

And then LIST to see the contents.

 

I did this and get a result but am unable to make it further and get errors or not found messages.

 

post-31910-0-67360400-1555018364_thumb.jpeg

 

Starglider is the title on the disk label. I tried:

 

load"starglider",8

 

and:

 

LOAD"Starglider",8

 

I also tried the same for the other two (titles?) that list, Paranoid and Para-Protect.

 

Maybe the disk is bad? Maybe the drive is bad? Or maybe my commands are wrong?

 

 

 

post-31910-0-30119700-1555018727_thumb.jpeg

Edited by gliptitude

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LOAD"*",8,1

 

It will load the first program on disk to its intended memory position, which often means it will auto start and load the rest.

 

So your got the computer to start again. Be careful so it doesn't die on you again. The PLA chip may have a tendency to stop working, and then it might work for a short while again.

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LOAD"*",8,1

 

It will load the first program on disk to its intended memory position, which often means it will auto start and load the rest.

 

So your got the computer to start again. Be careful so it doesn't die on you again. The PLA chip may have a tendency to stop working, and then it might work for a short while again.

Alright I got a title screen. But it was stuck there for so long that I gave up. I think I gave it about ten minutes. The disk drive was whirring away and the title screen would not be interupted by any input on the keyboard or joystick. I eventually just flipped the power switches off. Shouldn't it have finished loading in that amount of time? Or shouldn't I have been able to interupt the loading with the run/stop key or home or something?

 

.. The power problem is really bad and seems to be getting worse and worse. I'm not sure how to be careful besides not using it or buying one of the pricey custom power supplies.

Edited by gliptitude

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Yeah, ten minutes of floppy drive activity is a bit too much even without a turbo loader. I don't think you should expect to be able to interrupt things though, and if so you probably need to press the magical combination RUN/STOP + RESTORE.

 

A good after market power supply would protect you from the original PSU one day misbehaving, but if you at the same time may have a bad PLA chip in the computer, it would need to be addressed as well. I don't know which is the best or easiest way to progress. If you find out the PLA is bad, you're still at risk as long as PSU is unchanged.

 

Besides enirely custom PSU solutions, there are people who have designed replacement circuit boards for the original supplies, to replace the old, failure prone voltage regulator with a modern solution. However it would take some gutting to do the change, and if you're not a qualified electrician I suppose you might be breaking some laws by operating on the internals of a PSU but if you trust your skills it could be a bit cheaper solution to failure proof the PSU.

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Well I've just sold all the Commodore stuff locally so there won't be any more questions from me anytime soon. I'm a little sad to see it go but glad the new owner seemed to appreciate it and have ideas and plans for it. He brought his young son with him who I think he was trying to teach programming. Also he anticipated doing repairs to the computer and has experience with that. The two of them sat there and watched me load, list and run the graphics demo and listened to me explain my whole experience with this computer.

 

I'm definitely glad to have gone through the type-in process and seen it all work. Thanks for the assistance with this carlsson.

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