And 25% of the information recorded on a CD is not the core audio, but not all due to Reed–Solomon.
The C64 had 64K of ram and was launched in 1982, and remember the velocity of cost changes back then.
In 1977 an Apple ][ shipped with 4K of ram, but just in 1979 the Apple ][+ was sold for less money and shipped with 48K.
And remember that is 4K, 48K or 64K for all code and data.
Also remember that an audio only CD player cost ~$2,500 in today’s dollars at launch in 1984. They only added that 25% overhead because they had to at the time.
I’d imagine that all of this factors in. CD players at their launch were probably considerably more expensive than C64s, and CDs hold far more data than a C64 (or other personal computer of that era) could use. Cassette drives were cheap, and reliable enough.
not necessarily affordably; CD is 1.4 Mbit/s PCM, the Commodore Datasette was like 50 bytes/sec and I don’t know for sure what encoding it used. The Atari 410 I have uses frequency-shift keying.
And that loading was done while the plane was still on the ground. After it was loaded, the system ran from the data in memory, without using the cassette any more.
So if the tape cassette didn’t load, somebody walked back to the hanger and got a better copy to use. No danger to the flight, except a slight delay in takeoff.
Aww, man, does this mean I gotta drop and give you 50?
(Bolding mine)
Was the info on the tape actually “stereo,” or 2-track monaural or 4-track playing in only one direction? Did they use the standard speed or a faster one for better “fidelity”?
If the tape screwed up in flight, did they chuck it out the window?
The information density on the tape is effectively fixed by the tape composition. The other critical thing is how the data is encoded. The head design (especially gap width) and read/write electronics further restrict the information it is possible to store. How fast the tape runs, or how you access the tracks only affects the data rate.
Keeping all four heads in exact enough alignment to be able to read the data broadside is a challenge. Skew limits the data density you can achieve. That said, I doubt any cassette based system ever got to the point where this mattered. They were all very primitive. The most basic ones were just plain mono audio.
The QIC (quarter inch cassette) data tape used a single head and moved it across the tape to select each track, and the tape was driven back and forth over the head as you read the data. Horrid things.
Aside: Some “smart” toys of the era (like the 2XL “robot”) used all four tracks on a standard cassette for audio in the same direction, and the buttons switched tracks. So it’d ask a multiple-choice question, and then you’d press a button to choose a track, and one track would say “That’s right!”, while the others said “Sorry, that’s wrong”.
Which also meant that if you put the tape that came with the machine in backwards, or played a normal tape on tracks C or D, it’d play the sound backwards.
