74
votes
Did computer games for Commodore 64 really take "25 minutes" to load "if everything went alright"?
Theoretically it could take 25 minutes (or more), in practice it never did.
Theoretically it could, because the C-64's built-in tape handling routines had a data rate of about 300 bit/s. That's 37.5 ...
- 9,830
56
votes
Accepted
How do I extract the program from the Radiohead "Nude" tribute by James Houston?
First, many thanks for the great question. This may well be my favourite retrocomputing video of them all, so I contemplated having a look at the executable for a while myself. So, this is what I did:
...
- 4,142
56
votes
Accepted
What did it sound like when you played a cassette tape with programs on it?
It sounds like a high-pitched noise, somewhat like you would hear from a modem. Here's a little TRS-80 Model 1 BASIC program that plots every pixel on the screen:
10 FORY=0TO47
20 FORX=0TO127
30 SET(...
- 7,656
48
votes
Accepted
Loading ZX Spectrum tape audio in a post-cassette world
If (and only if) your audio player is battery powered, and your Spectrum is the 48K or 128K toastrack model, try the following procedure, intended to boost the volume of your wave signal, as seen by ...
- 18.6k
31
votes
Accepted
How did ZX Spectrum games loaders prevent the use of MERGE?
Each line of BASIC is stored in memory as two bytes for the line number, then two bytes indicating the length of the line in bytes, followed by the tokenised text of the line. MERGE protection works ...
- 1,341
28
votes
Accepted
How did "full memory" Spectrum tape copiers work?
These programs usually had a mono-color background with very little text. By setting the color of the screen as "black ink on black paper" or "white ink on white paper", it is possible to relocate the ...
- 1,233
26
votes
Accepted
Blue and yellow stripes on the screen when loading from tape on ZX Spectrum
Actually, the screen stripes while loading from tape first occurred on the ZX-81 - Where they were a result of Sinclair's typical savvy nature - the display and the "EAR IN/MIC OUT" had to share a pin ...
- 33k
26
votes
Did computer games for Commodore 64 really take "25 minutes" to load "if everything went alright"?
Yes, cassettes were common, they took ages, and they were error prone.
In Europe, disk drives for the ZX Spectrum and Commodore 64 were uncommon. It's the same for cartridge games for the C64. The ...
- 261
24
votes
How did "full memory" Spectrum tape copiers work?
There are multiple techniques used by tape copy programs to be able to copy large blocks of data. By large we mean close to the whole RAM capacity (48 KiB) or even more!
Using maximum of the ...
23
votes
Did any microcomputers back in the day accelerate standard-cassette performance
The Sprint cassette player/recorder, specially designed for the ZX Spectrum, allowed 4X load and save speeds.
It works by speeding up the tape four times the standard playing speed. It is meant to ...
- 18.6k
23
votes
Accepted
Rescuing data from old audio cassettes
There's so much to go wrong in a cassette mechanism that it's amazing they worked at all.
can you adjust tape head azimuth? Misalignment is responsible for a lot of sound problems.
how clean are your ...
- 20.6k
23
votes
Accepted
Which software was the first to use copy protection?
I couldn't say which one was the first but there were early efforts in the 1970's and 1980's
Encrypted roms
Arcade games were often hacked so ROM encryption was developed, so if the board was re-made ...
- 10.7k
22
votes
Copying tapes "back in the day"
In theory, it is fairly simple duplicating a tape.
The problem with analog tape-to-tape copies is that sound quality lowers and spurious noises are also copied and more are generated into each new ...
- 2,590
20
votes
Loading ZX Spectrum tape audio in a post-cassette world
I've confirmed that mcleod_ideafix's method is reliable for regular tape images. Here is a shell script to do (effectively) the same thing:
#!/bin/bash
# wav2differential.sh - convert mono game tape ...
- 20.6k
20
votes
Why did some Spectrum games need LOAD "" CODE?
As you guessed,
LOAD ""
loads a BASIC loader.
LOAD "" CODE
loads a machine code program saved on the tape straight into memory, at the addresses given when using
SAVE name CODE start, length
...
- 2,903
20
votes
Accepted
Did the Apple 1 cassette interface card have its own ROM?
The Card featured 256 bytes of ROM.
Is there evidence documenting how the cassette program was stored?
The evidence is right there in the PCB photo you added. The two MMI 6301 chips, labled APPLE A3 ...
- 213k
19
votes
Accepted
Why does waggling the joystick of a C64 cause errors loading from tape?
Commodore 64 uses two CIA (Complex Interface Adapter) chips. CIA#1 is responsible for the keyboard, joystick, paddles, datasette and IRQ control, while CIA#2 controls the serial bus, RS-232, VIC ...
- 2,728
19
votes
Accepted
Compression techniques used in old ZX Spectrum tapes
I don't recall any mass-market commercial software for the Spectrum using the term "decrunching" - I'd associate that more with the demo and cracking scenes of central and eastern Europe, ...
- 1,341
19
votes
Why Kansas City Standard (KCS/CUTS) differs from Bell 103/202/212 modem protocol?
They are different because they are meant for different use cases so they both work well for what they are meant for. One is suitable for real time data transmission between two distant equipment over ...
- 28.3k
19
votes
Accepted
How did the Commodore 64 show a picture while reading cassette?
TL;DR Should not be a problem.
There are two separate issues:
predictable timing
Actually, I would expect that standard video memory access and similar things would have very predictable timing. I ...
18
votes
Cassette tape storage formats
The simple reason is that interoperability was not a primary drive for this kind of storage, especially at the consumer level. Honestly, what's the point of reading a Commodore cassette on an Atari ...
- 12.2k
18
votes
How to decode an audio file which contains an MSX BASIC program?
You need to use OpenMSX, and get the system ROMs for the machine in question. Then run OpenMSX, set the machine to the FS-A1WSX. There's a little menu button at the top left of the OpenMSX window. In ...
- 3,857
18
votes
Did the Commodore datasette interface provide greater reliability?
The Datassette has a digital interface, and since it is not meant to process audio signals at all, it allows directly writing sharp digital magnetic transitions to the tape, using a single monophonic ...
- 28.3k
18
votes
What did it sound like when you played a cassette tape with programs on it?
I understand this question is about the Tandy, so I'll move this to a self-answered question if necessary, but I believe you'd be interested in this information. On a ZX Spectrum (at least, the ...
- 11.8k
17
votes
Accepted
What format is used for Apple II cassette tapes?
The Apple II recorded data as a frequency-modulated sine wave. A standard consumer cassette deck could be connected to the dedicated cassette port on the Apple ][, ][+, and //e. The //c, ///, and ...
- 8,775
16
votes
Blue and yellow stripes on the screen when loading from tape on ZX Spectrum
No, they're purely for communication with the user. Coloured stripes = loading, slow colour changes = not loading.
Setting the border colour on the Spectrum is achieved with a simple port output. The ...
- 36k
16
votes
Accepted
Does lossy audio compression damage datasette data?
TL; DR type of answer:
In short, MP3 is a lossy format that does distort the audio waveform in which the C64 data is stored, but just like you can still listen to morse code or music just fine on a ...
- 28.3k
16
votes
Which software was the first to use copy protection?
One of the earliest would likely have been Microchess 2.0 for the Apple II, shipped on cassette in 1978. Andy McFadden's Early Copy Protection on the Apple II article has the details.
- 20.6k
15
votes
Accepted
Why did the Atari 8-bit computers make beeping noises while accessing the disk and cassette drives?
The beep comes from the OS ROM, and it is actually derived from the timing of the start and stop bits of each byte shifted into POKEY, this is determined from the interaction of the interrupts ...
15
votes
Accepted
Why did the ZX Spectrum use edges for its tape storage routines?
I'm not sure what you mean with "EAR/MIC I/O was level based". In the ZX Spectrum, the EAR input is a digital input, so it can only be 1 or 0. You cannot measure the input level beyond that.
The main ...
- 18.6k
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