Saving programs to disk

Saving programs to disk

Postby KayBee » Mon May 02, 2016 9:09 am

May I ask some Atari advice? Back in the 80’s I had a Commodore 64. The 64 used a disk drive called the “1541.” This drive had the appropriate ROM and disk OS, so using a drive required no special workflow when using disks. Put in the disk, save and load exactly like cassette. Atari is different, where a program that requires 16k to run on cassette requires 8k more if on disk. I think there is a disk workflow that I have to understand before I can understand how to use your cool software (along with SIO to PC USB hardware). Like the disk must be specially prepared with DOS on it or something. Is there a tutorial you can point me to? Or, am I mistaken?

Many thanks.

KB
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Re: Saving programs to disk

Postby Ray » Thu May 05, 2016 4:23 pm

Nope you're not mistaken. All Atari 8 bit computers require a DOS (Disk Operating System) to load into the computer before they can access disk drives (unless a software on the disk already has disk operating code embedded in it). Before they can be used, disks (floppies) need to be formatted. Here's a short explanation of the boot process:

- Insert a DOS diskette into your drive (drive id must have been set to 1 in order to boot the computer)
- Turn the drive ON
- Turn the computer ON.
- The first 3 sectors of the disk is read from the inserted disk. These sectors are called boot sectors and Atari's built-in OS knows how to read the 1st 3 sectors
- Those 3 sectors contain code to locate and load the DOS from the rest of the disk. On a DOS diskette the file loaded is called DOS.SYS
- When DOS is loaded, you now have a disk manager who knows how to access disks with directory structures and control is returned to the built-in BASIC and a READY prompt appears on your screen.
- If the Atari doesn't have built-in BASIC (like Atari 400/800/1200XL computers), then a file called DUP.SYS is loaded from the disk next. This is the DOS Menu or Disk Utility Program.
- If the computer does have built-in BASIC (or a BASIC cartridge was inserted in the cartridge slot), the DOS menu can be loaded manually by typing DOS from BASIC'S READY prompt.
- If there is no disk drive attached to the computer DOS is not loaded and the computer boots into BASIC. In this case you can not do any disk operations with the computer until you reboot with a DOS disk attached.
- If no disk drive is present and there is no built-in/cartridge BASIC in the computer, the computer will either land into a Self-Test mode screen (XL/XE computers), to a blank screen called Memopad (400/800) or to an animated Atari logo screen (1200XL)

- Once the DOS is loaded you can then do all sorts of I/O from BASIC, or save/load files, format disks from the DOS menu.

This is the basic workflow of the boot process of Atari 8 bit computers. There are some more details of course but I don't have a reference to a complete documentation at this time.
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Re: Saving programs to disk

Postby KayBee » Sat May 07, 2016 3:43 pm

Excellent, I was missing that little piece. Hard to get my head around it, so used to other systems I had some kind of cognitive block. I am now successfully loading and saving my basic programs to my Win7 box painlessly via AspeQt (love it) and SIO to PC device (rad).

Nicely done, thank you.

KB
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Re: Saving programs to disk

Postby Ray » Sun May 08, 2016 4:08 am

You're very welcome, glad to be of help.

PS: Should you need more info on how to do disk operations from Basic you may want to read this, if you want to directly access the serial port and implement your own I/O routines you need to read and understand SIO which is the lowest level of serial device access method, in this case you dont need DOS.
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