What is a SEQ file?

[chysn]

Yeah, what is a SEQ file? From context, it seems that it's maybe a file without the two-byte address header that PRG files have, but I'm not sure if that's right.

If that's not correct, is there a Commodoreverse name for flat files with no address header?

[Mike]

Yeah, what is a SEQ file?

It is a file containing SEQuential data.

From context, it seems that it's maybe a file without the two-byte address header that PRG files have, but I'm not sure if that's right.

CBM DOS offers this file type designator to discern 'raw' sequential data from PRG files, of which the KERNAL interprets the first two bytes as load address.

There is also the CBM DOS file type USR, which stands for USeR file. You often find them (somewhat misused) as another 'type' of SEQ files, but they are actually supposed to be loaded into floppy RAM and executed there, via the "&" command. Think of them as a kind of PRG files for the floppy drive. Their format is somewhat complicated though and it includes a checksum, so they are not used that often.

[chysn]

Yeah, what is a SEQ file?

It is a file containing SEQuential data.

OK, thanks. I've been creating some SEQ files with OPEN8,8,1,"FILE,S,W" and I think I see how they work. I'm simulating storage of various types of VIC-20 files via Bluetooth, and it looks like storage of SEQ files requires an explicit address to be set, because there's no information about where it goes. The alternative is that the application that created it knows what to do with it, whether it's saved to memory or handled on a just-in-time basis.

If a file is created with the above OPEN on a real-life hardware 1541 drive, can the drive identify it as a SEQ file, or does everything just show up as a PRG in the directory listing, like it does in VICE?

[srowe]

If a file is created with the above OPEN on a real-life hardware 1541 drive, can the drive identify it as a SEQ file, or does everything just show up as a PRG in the directory listing, like it does in VICE?

The standard directory listing shows them as 'PRG' on the right yes.

[groepaz]

does everything just show up as a PRG in the directory listing, like it does in VICE?

Say what? That only happens if you use the native filesystem - of course VICE shows them as SEQ and USR files if you are using a proper disk image.

That said - at the end of the day PRG, SEQ and USR are exactly the same thing, the only difference being one byte in the directory entry. As soon as you are making your own software they are pretty much equivalent.

[chysn]

does everything just show up as a PRG in the directory listing, like it does in VICE?

Say what? That only happens if you use the native filesystem - of course VICE shows them as SEQ and USR files if you are using a proper disk image.

I am using the native filesystem. When I create the SEQ with a disk image, it does show it as SEQ in the listing.

Thanks, all! I think I understand this now.