Program to speed up floppy disk access?

[BarryB]

Some games I've played seem to have a 'turbo load' where the disk drive loads much faster than normal, is there a DOS program that will do the same?

[s2325]

Maybe just try to find crunched version of games - loading time is shorter. I think adjusting reading speed may be dangerous to drive and floppy disks.

[ma693541]

This reminds me about a program that played some music from a empty diskdrive, that was moving back and forth on the driveheads.

[BarryB]

Originally Posted by ma693541

This reminds me about a program that played some music from a empty diskdrive, that was moving back and forth on the driveheads.

Similar to this one but with disks in: [ Show youtube player ]

@s2325: It's a crunched game I want to load quicker I seem to recall there was a CLI util that did this but can't for the life of me remember what it was.

[Leffmann]

Try hackdisk.device, you can find it on Aminet.

[BarryB]

Originally Posted by Leffmann

Try hackdisk.device, you can find it on Aminet.

Don't think that works from bootable floppies, and you'd have to faff around getting it to run from a floppy!!

However, I dug out some old compact menus I made in 89' and on one of them is a program called 'SPEEDLOADER', hex editing shows trackdisk.device being used but it doesn't seem to speed floppy access up on my A500 1.3 or A1200 3.1. I had a 1.2 back in the day so maybe it only works with that?

Anyway, i've attached it to this post so if anyone can look at it and see what it actually does i'd appreciate it.

[DaveMB]

Originally Posted by BarryB

Similar to this one but with disks in: [ Show youtube player ]

this one is better
[ Show youtube player ]

[BarryB]

Originally Posted by DaveMB

this one is better
[ Show youtube player ]

It's the same people that did Dr Who, didn't know they did any others.

[hooverphonique]

well, if that were possible, don't you think commodore would have done it like that already?

you might be able to speed up physical loading speed slightly, but it will be a compromise that won't work on all drives, depending on their seek/settle times.

some games/demos used to just read one side of the disk, resulting in a stepping speed close to double, maybe that's what you've seen?

[desiv]

Originally Posted by hooverphonique

well, if that were possible, don't you think commodore would have done it like that already?

You mean like with their 1541 drive on the C64?
No way to add routines to add a FastLoad (c) there. ;-)
(The Amiga guys were more thorough tho.. Commodore, I'd actually expect it..)

It's possible I suppose, but I don't remember ever seeing a program/hack for speeding up an Amiga drive back in the day..

desiv

[BarryB]

Originally Posted by hooverphonique

some games/demos used to just read one side of the disk, resulting in a stepping speed close to double, maybe that's what you've seen?

Yep, that could explain it, layout the files so they fill one side of the disk first then fill the other side. If that's so, what would I use to do that? Could I format a disk and edit the bitmap to say the odd tracks were used, copy data to the disk then edit it to say those tracks were now empty and copy the rest of the data to it?

[mark_k]

You could do something like that, kind of. But it won't improve loading speed. Stepping the heads to the next track is slower than switching from lower to upper head. So it sounds like it's loading faster, but isn't. You best bet would be to just use a disk optimiser like ReOrg.

There was a floppy-speeder type program listed in the book Amiga Disk Drives Inside & Out. Apart from (probably) reducing head step timings, it probably did a whole lot of illegal things so wouldn't work on later Kickstart versions. I seem to remember some code listed in that book jumping to absolute ROM addresses.

Another approach would be to allocate contiguous sectors in the disk's bitmap then put the data you want in those sectors, loading it using trackdisk.device. But that limits your program to work with floppy disks.

[hooverphonique]

Originally Posted by mark_k

You could do something like that, kind of. But it won't improve loading speed. Stepping the heads to the next track is slower than switching from lower to upper head. So it sounds like it's loading faster, but isn't.

Exactly!


Another thing is to do mfm decoding using the blitter or the cpu, depending on the system configuration (cpu type, fastram, etc) and the destination address of the data, but it's hard to come up with a general prescription on how to load faster from floppies, unfortunately..

[IFW]

The maximum speed you can achieve is limited by the speed of the disk rotation, ie at 300 RPM gives you 5 tracks per second. You will also need to time settle the head after a step, until that happens you read garbage/skewed data. Also need time after switching sides.
Additionally, with extra hardware and/or more efficient encoding you can record more data per track.
That's all you can do - if you already have a loader that can read and decode a track in a single revolution with the head settling delay added after stepping you've already reached the physical limits of the hardware; it won't get any faster ever.

[BarryB]

Well I'm no coder so I can forget writing any sort of track loader!! Did anyone have a look at the speedloader program and see what it actually does? Pity you can't use a CF card or SD card in place of a floppy, or can you??

[demolition]

You can use a device called HxC. It emulates a floppy drive using images off an SD card. It's not any faster though as it emulates the original floppy drive speed for compatibility reason. Not sure if it can be set to a faster mode for other uses.

[BarryB]

That kind of defeats the object though Think that's why WinUAEs floppy speed emulation corrupts some disks when set to 400 or 800% but appears to be fine at 100 or 200%

IFWs explanation makes perfect sense though, unless the RPM increases (and the hardware adjusts) you can't read stuff any faster than the drives original speed allows.

So just what the heck did that speedloader do?

[Cymru]

The Amiga team had a load routine to get the A1000's KickStart into ram very quickly. You can find the use of these on Aminet in the small programs ReadKwik and RiteKwik in the file DosKwik.lha; the speed to fill a RAM disk is quite amazing.

[Toni Wilen]

There are some ways to speed up physical loading speed without hardware modifications:

- step faster (no real difference if you want to stay inside specs and stay compatible with older drives..)
- decode MFM while reading/stepping to next track.
- optimized MFM decoding (KS 1.x MFM decoding isn't that fast, for some reason A1000 KS loader seems to be faster, probably because it does not need to be multitasking friendly)

Amiga does not use sector interleave and it does not have any data transfer bottlenecks like C64 does. Data transfer is real-time DMA. It can't be sped up or slowed down but it has some tolerance to motor speed changes, +-5% or so.

[pandy71]

Originally Posted by Toni Wilen

Data transfer is real-time DMA. It can't be sped up or slowed down but it has some tolerance to motor speed changes, +-5% or so.

Higher clocking is easily doable and it will speed up DMA but based on my experiments not much - AFAIR limit was around 30MHz for SYSCLK but for disk written with higher speed this limit should be approx twice higher but still way bellow 50%.