Sunday, January 30, 2011

Retrochallenge Success!

To recap - my goals for the Retrochallenge 2011 Winter Warmup were:

  • Build a cable to connect the Commodore SFD-1001 drive to the PET 2001-8N.
  • Test the cable and the drive by successfully formatting a disk, saving a program, then re-loading that program into memory.
  • Get some software from the Internet, load it into the PET, then save it to the SFD-1001.
Having done the first two steps, I set out this evening to finish step 3 - getting some bits from the Internet to the PET. And - success!

(With one caveat - I actually created the program that I moved from my PC to the PET/SFD-1001, using VICE. But it could have been a PRG program from anywhere.)

Here are the steps I used to get the program from my PC to the PET, then to the SFD-1001:

Create program in VICE

I typed a small (very!) program into the VICE Commodore PET emulator program, then saved it to a virtual tape file ("TAP" file). It's pretty easy to create and use a virtual tape image in VICE. I'll leave the "how" as an exercise to the reader, but you'll figure it out in less than a minute.

Create a WAV file with an analog C2N-compatible audio image of the program

Next, I used a program called "Audiotap" that converts a virtual TAP file into an audio "WAV" file.

This program prompts you for the *.TAP file, then for the output *.WAV file. It then creates an audio WAV file that reflects the same signal you'd hear as created/used by a real Commodore C2N cassette drive.

Record the WAV file to tape

Now, creating this file and recording it to a cassette deck was pretty easy. Getting it to read on the PET was hard. The audio levels had to be adjusted properly, and I actually had to switch computers once. I was trying to use my laptop for this, but its sound output is too noisy. I eventually switched to my desktop, which has a SoundBlaster Audigy 2 ZS, and this was squeaky clean. Here's the mono cassette deck I used:

Load the program from C2N tape into the PET

Once the WAV file was recorded on the tape, then I moved it to the C2N cassette deck, and attempted to load the program from tape.

As I mentioned, getting the analog levels correct was tricky - but once done, things were looking up!

Save the program to the SFD-1001

With the program successfully in memory, I wasted no time in saving it to the SFD-1001:

Test that it all worked

With the program safely moved from the PC to the PET to the SFD-1001, I then did a cold-start (just to make sure there's nothing up my sleeves), and loaded the program back from disk:

Voila! Bits moved successfully from the PC realm to the PET via good ol' cassette tape, then tucked safely away on disk.

The future

As I've been reading up on moving programs between the PC and the PET, I've found that there are several options, all of which are better and more sophisticated than the cassette tape proxy method that I just performed. I'll be looking into these, perhaps building some more hardware, and then will blog with future results.

But for now, I will bask in the bright light of Retrochallenge success!

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