Re: IDE for C64

From: Marko Mäkelä (
Date: 1998-12-05 16:52:43

On Sat, 5 Dec 1998, Ruud Baltissen wrote:

> If I have to use an extra computer anyway, then why not an obselete 1541
> or 1571. 

Because they might be more difficult to obtain than the parts for building
a custom 6502 computer?  On the other hand, building everything from
scratch is more expensive and time-consuming.

> Nonsence! Just think how an emulator uses his emulated 1541. In reality you 
> tell it to use a simple file as floppy.

You can call the disk images files or partitions; the reality doesn't
change: you will have to divide the hard disk to hundreds or thousands of
disk images in order to use it in that way.  A higher-level file system,
without any 1541 compatible block-read or block-write commands or file
structure is necessary.  The reality is that using 2-byte sector links in
the beginning of 256-byte sectors limits the maximum file (and disk) size
to less than 16 megabytes, which is less than 1% of the capacity of modern
hard disks.

> I give you the ideas I'm thinking of (for the moment):
> - 32-bits FAT, a cluster = 1 sector. This means you lose 4 bytes on every
>   sector of 512 byte (= < 1%).

Will the whole file allocation table fit in the memory?  How do you
address fragmentation problems? 

I wish you good luck with the project.  I don't want to discourage you
from doing it; I just wanted to point out some things that might become
problematic later.


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