Re: PRODOS and cassettes

[schmidtd <schmidtd@my-deja.com>]

On Nov 28, 8:28 am, Jeremiah Stoddard <jerem...@jeremiahstoddard.com>
wrote:
> Does anyone know how I can access Applesoft's LOAD and SAVE
> commands while PRODOS is loaded?
You would have to patch the ProDOS BASIC Interpreter to get the
commands back.  I didn't immediately see an easy solution out there,
but I imagine one exists in ready-to-use form.

> I would like to be able to transfer some BASIC
> programs between cassette and disk...

How much fun do you want to have?  The SAVE command wrote out two
blobs of data to the cassette, each with a 10-ish second leader:
first, 3 bytes that defines the next blob's length, plus this blob's
CRC.  Next comes (length) bytes of data, followed by that blob's CRC.

So, to load by hand, you'd:
0. Type NEW
1. Rewind the cassette
2. Enter the monitor: CALL -151
3. Load the first blob.  Enter: 801.803R
4. Press play on the cassette
5. When the Apple BEEPs, hit stop on the cassette.  Quickly!
6. Examine locations 801 and 802: 801.802
7. Let's pretend the resulting values were 32 and 04.  Swapping the
order, we get $432. That's the length of the next blob on the cassette
once we hit play again.
8. Add $432 to $801 = $C33
9. Load the second blob. Enter: 801.C33R
10. Hit Play.  Cross fingers.  Wait for the BEEP.
11. Hit Ctrl-C to get back to BASIC.

If the read was good, you'll have the program ready and waiting in
memory.  If you get a beep but ERR, there was a checksum error.  Check
the volume level, tone control, connections, etc. and try again.