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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 ...
Michael Graf's user avatar
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55 votes
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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: ...
introspec's user avatar
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55 votes
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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(...
George Phillips's user avatar
48 votes
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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 ...
mcleod_ideafix's user avatar
31 votes
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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 ...
gasman's user avatar
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28 votes
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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 ...
Sklivvz's user avatar
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26 votes
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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 ...
tofro's user avatar
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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 ...
user19766's user avatar
  • 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 ...
pabouk - Ukraine stay strong's user avatar
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 ...
mcleod_ideafix's user avatar
23 votes
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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 ...
scruss's user avatar
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23 votes
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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 ...
Jean-François Fabre's user avatar
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 ...
Rui F Ribeiro's user avatar
21 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 ...
harlandski's user avatar
  • 2,953
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 ...
scruss's user avatar
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20 votes
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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 ...
Raffzahn's user avatar
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19 votes
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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 ...
wizofwor's user avatar
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19 votes
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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, ...
gasman's user avatar
  • 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 ...
Justme's user avatar
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19 votes
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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 ...
manassehkatz-Moving 2 Codidact's user avatar
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 ...
Will Hartung's user avatar
  • 12.3k
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 ...
Alan B's user avatar
  • 4,730
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 ...
knol's user avatar
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17 votes
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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 ...
fadden's user avatar
  • 9,060
17 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 ...
Justme's user avatar
  • 33.7k
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 ...
Tommy's user avatar
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16 votes
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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 ...
Justme's user avatar
  • 33.7k
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.
scruss's user avatar
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15 votes
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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 ...
Thomas Cherryhomes's user avatar
15 votes
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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 ...
mcleod_ideafix's user avatar

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