.R00 File Format

Introduction

A PC64 REL file holds one Commodore 64 relative file: a file of fixed-length records that a C64 program can read or write by record number. PC64, a C64 emulator for the PC, keeps each file of a C64 disk as a file of its own on the PC's disk, with a 26-byte header in front that holds the file's real C64 name. The extension is the file's C64 type letter, here R, and a counter: .r00, and .r01 up to .r99 when two C64 names reduce to the same DOS name. The header is the same as for the other types, described on the P00 header page; for a REL file the byte at $19 is the record size and is not zero.

Both sources found for the format say that a REL file needs no side sectors in this container, unlike a D64 disk image or an LNX or ARK archive, and give the record length and nothing more about the data. The explorer therefore shows the header, the record size and the data as bytes, and states how many records of that size the data holds (plain arithmetic: the format description does not say how the data is laid out).

Not a RAR volume

Old multi-part RAR archives are named the same way: NAME.rar, then NAME.r00, NAME.r01 and on to NAME.r99. The two have nothing in common except the name. The explorer looks at the first bytes: a file that starts with Rar!, $1A, $07 is shown as a RAR multi-volume part, one that starts with C64File and a zero byte is shown as a PC64 REL file, and a file that is neither is shown with the first of the two names.

Not described

Known, not yet covered

• Reference: the layout of the data of a REL file in this container: Schepers' PC64 document and VICE's reader give only the record length in byte $19.
• Viewer: the records are not split into rows; the data opens as bytes.

Unknown

• Reference and viewer: no real PC64 REL file was available; the viewer was tested on built files only.

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