1000kb on a DD floppy disk

[burnsflipper]

Not sure which forum to put this in, but this is something I wanted to share.

In 2000 I used to download stuff off the aminet. After a while I decided to back up the useful archives to disk. Since we had no CD-R back then, nor HD floppy drives cheaply available, I would store everything on all the DD floppy disks I had spare.

I used to get 1000kb on them. I bought PFS as soon as I heard about it (Professional FileSystem) and used this for my hard drive, and found that I could format a disk using the PFS filesystem and the diskspare.device that used to come on magazine coverdisks (so they could get more onto the disk), and I'd fit exactly 1000kb on a DD floppy. All it took was a custom file in Storage/DOSDrivers which I'd mount when I wanted to use it.

I called it PS0: and used a util off the aminet to fill it (AFill, which works out which set of files can optimally fit on a disk). I wrote a custom script which would pop up a drawer selector and pass your selection to Fill, and it would move files totalling exactly 1000kb onto a disk, no more, every time.

The contents of my PS0: file are:

FileSystem	= l:ProfFileSystem
Device		= diskspare.device
Priority	= 10
Mount		= 1
Unit		= 0
Flags		= 0x12	/*	verify | DD only | 82 Cyls 	*/
Surfaces	= 2
BlockSize	= 512
BlocksPerTrack  = 12
Reserved	= 2
Interleave	= 0
LowCyl		= 0
HighCyl		= 81
StackSize	= 5000
Buffers		= 5
BufMemType	= 1
GlobVec		= -1
DosType		= 0x50465300
MaxTransfer 	= 2097152
Mask		= 0x7ffffffe

[Nobby_UK]

From my old mount list:

/* DiskSpare mount entry - Flags 2=960, 3=984, ?=1920, 7=1968 Kbytes */
/* Where HighCy =79, 81, 79, 81 */
DS0:
Device = devs:diskspare.device
Mount = 1
Unit = 0
Flags = 3 /* = 984 k */
Surfaces = 2
BlockSize = 512
BlocksPerTrack = 12
Reserved = 2
Interleave = 0
LowCyl = 0
HighCyl = 81
Buffers = 50
BufMemType = 0
StackSize = 600
Priority = 10
GlobVec = -1
Mount = 1
DosType = 0x444F5301
#

[jizmo]

I used diskspare.device first and formatted about 100 of my disks with the device name of DS0:, then discovered Professional File System and formatted a few tens of my disks with the device name PF0: until realising I can actually combine the two and used the device name PS0:, and had about 300 of my disks (out of roughly 800 disks in total) in this format. So, I had five different device names that refer to floppies in the end; DF0, DS0, PF0, PS0 and PC0 (for those few PC formatted disks I used in school).

When I got back to Amiga some 15 years later, and made an attempt to back up the whole collection you can imagine the entertaining time I had figuring out these formats again

I still have a few zip disks laying around that I'm pretty sure I formatted with the same kind mix of formats, so once I feel motivated enough to get me a drive again, I have that mountain again to be scaled.

[ElectroBlaster]

I vaguely remember doing this many years ago!

I began to think I had imagined doing it, but trawling through thousands of my floppies I did come accross one with an unreadable format but I wrote on it that it held more than it should, not high-density and that it had worked.

I may go and look for that disk later.

[burnsflipper]

That's neat that we all did the same thing.

Maybe we should have a competition of the most number of stable bytes stored uncompressed on a DD floppy disk.

[jizmo]

Originally Posted by burnsflipper

That's neat that we all did the same thing.

Maybe we should have a competition of the most number of stable bytes stored uncompressed on a DD floppy disk.

It's cute alright. I was so happy to fit all that data in a disk and back then my dream was to one day own a HD floppy disk drive so that I could put whopping 2000kb of data in there

I never did have any problem with either one of the formats. If there was a read error it was due to the disk being physically broken and would not work any more in any format. Those disks I formatted with a program that blocks out the bad sectors in a file inside the disk to prevent trying to read or write data off them and handed or mailed those out whenever someone needed something from my collection.

[burnsflipper]

This is uncanny, I used to use that program too. It found the bad sectors and created an entry in the file table with the location of all the bad sectors as the locations of the parts of a file. The file didn't really exist, it was just a clever manipulation of the file table. As long as you didn't delete the file or defrag the disk using ReOrg, it made bad disks usable.

[AmigaHope]

It got even crazier with xfloppy.device. 1.1M on a DD 3.5" floppy. D=

[jizmo]

Originally Posted by AmigaHope

It got even crazier with xfloppy.device. 1.1M on a DD 3.5" floppy. D=

Luckily I parted ways with Amiga right before it came out. My floppy disk collection would've ended up a total mess