Can a Geneve boot off of an 80 track TIFDC?

[+jedimatt42]

So, I'm goofing around with the Geneve emulation in mame. And as I am want to do, I like to set up minimum system, and a maximum fantasy system, and something close to devices I actually have or believe to be eventually obtainable (seriously subjective criteria )

 

I have been able to get mame Geneve emulation to boot from a TIFDC using a double sided single density DSSD 40 track image. But it fails to read a DSSD 80 track image. Is that a limitation of the Geneve boot rom? or is it a limitation of the mame emulation (maybe cause it doesn't have the 80track DSR image for the TIFDC)?

 

Does a real Geneve use the hardware's DSR rom to boot? Would it ignore the 80 track state of a modified TIFDC and still boot a 40 track image?

 

 

[+mizapf]

Hi jedimatt42,

 

1. Please use the HFDC; there is no reason to use the inferior TIFDC.

2. If you want to use 80 track disk you also need to use an 80-track floppy drive. You'll have to use a 3.5" option ("-peb:slot8:hfdc:f1 35dd", if your HFDC is in slot 8 ).

Edited November 27, 2015 by mizapf

[+mizapf]

I just re-read your message; you want to experiment with different configurations. OK, then you can, of course, use the TIFDC, but still you need to use a 80-track drive as said above. For an everyday system I would recommend to use a harddisk. I included a harddisk prepare feature in TIImageTool so you just need a few mouse clicks to get a bootable Geneve drive.

 

(In the recent MAME/MESS releases I added the PFM512, so you may want to have a look.)

Edited November 27, 2015 by mizapf

[+jedimatt42]

Oh! I get it! I wasn't controlling the drive type for the emulation. Cool!

 

On this US Thanksgiving holiday, I am thankful that the internet is international, and that I don't have to go to work tomorrow so I can play with this!

 

I saw in the OSD options with the hfdc the drive type, but it only seemed to be empty or 525dd. And no similar option on the TIFDC. I will update my mame install and take another look!

 

Thanks.

[+mizapf]

One word of caution: Don't laugh, I'm really talking about the emulation, not the real drive.

 

When you use an 80-track drive, and you write to a formerly 40-track-formatted disk image, you will not be able to read that image in a 40-track drive anymore.

 

The reason is that the emulation will autoconvert the 40-track image to an 80-track image when used in an 80-track drive. When you do a write operation, it will be committed back to the file, which suddenly grows to double size.

 

This is quite in accordance to the real situation. When you use an 80-track drive, it will either access each track (80-track medium) or perform double-stepping (40-track medium). When the drive head writes the flux, it will only change one half of the track. This will become unreable in a 40-track drive. Indeed, for an 80-track drive, a 40-track medium looks somewhat like an 80-track medium with two instances of the same track (twice 0, twice 1, ...). And when it writes, it will only change one instance.

[+jedimatt42]

That's good to know, that would be very mysterious behavior to casually observe.

 

I only have 80 track drives for real iron, so I had never tried to work with a 40 track disk in there before, but with emulation and .dsk files flying around, it would be easy to make that mistake.

 

Thanks!

[+jedimatt42]

The answer to the original question in the topic title, is NO.

 

SYSTEM/SYS can be loaded off of 80 track disk in 80 track drive on TIFDC with 80 track DSR. But once SYSTEM/SYS is loaded, the DSR is ignored, and AUTOEXEC and any other file won't reliably be read.

[+InsaneMultitasker]

Type 'setdsk' at the command prompt. It will show you the settings for each drive. If the setting ends in '4' the os is setting the drive to 40 tracks. Replace the '4' with '8' and type with the command as follows.

 

SETDSK xy8 where x is th drive number and y is the step rate. Then try cataloging.

 

I do not recall whether a device test for the 80 track ti card was ever implemented.

 

Also, if the ti card uses 16 sectors per track, be warned the Geneve may use 18. Do some testing before you commit.

[+jedimatt42]

Is that something that can be set by CYA as well? so that loading the AUTOEXEC will work?

 

-M@

[+InsaneMultitasker]

Yes. Just be aware - once you use cya, the system will not auto detect the floppy drives. You must select them manually in cya. This can be a gotcha if you swap controllers. Always keep an unmodified copy of the os available.

[+jedimatt42]

Nice. The only documentation I've found on CYA indicated it is licensed software, not freely distributed. Has that changed?

And from that documentation I had made the assumption CYA only displayed this info for HFDC.

 

Is the latest version of CYA that can do this, the one distributed in the Mdos650.ark on whtech?

[+InsaneMultitasker]

Yes, if the arc is the full distribution disk. The commercial license is no longer in effect.

[+jedimatt42]

So I finally got around to trying this. And it doens't really work..

 

setdsk 128 works fine... and then I can operate on 80 track disks... but I cannot boot an AUTOEXEC off of an 80 track disk because setdsk 128 hasn't been run yet.

The CYA feature to set tracks checks if you have a HFDC first. Since I'm using a TIFDC only, it does not allow me to go any further.

 

To recap:

The Geneve will load SYSTEM/SYS off of the TIFDC/80-TRACK-MOD with an 80 track HFE in my Gotek drive.

SYSTEM/SYS will not load the AUTOEXEC from the 80 track HFE.

All boots fine from a 40 track HFE

I can call setdsk 128 and load goodies off of 80 track HFEs after boot is complete.

 

Since there was some literature that said CYA was about eliminating the practice of hex editing SYSTEM/SYS, is there information somewhere on the old hex-editing tricks that might work for this scenario?

[Mad Hatter]

I don't know if this will work, but you can get your system booted from your 40 track drive as you stated, then type SETDSK 128 from the command line. CD to your 80 track HFE, and If you have a program called TESTH, type TESTH SYSTEM"/"SYS from the command line. This will reload whatever SYSTEM/SYS you have in the directory, even if it is a different version from what is currently loaded. Like Insane stated, if you have modified your SYSTEM/SYS with CYA then it will not search for the floppies to boot the AUTOEXEC. So use an unmodofied version.

 

(Although after thinking about it, there isn't really much point in doing this as you've already booted the system once, and as you said, everything works fine once you SETDSK 128 afterwards)

Edited December 6, 2015 by Mad Hatter

[+InsaneMultitasker]

So I finally got around to trying this. And it doens't really work..

 

setdsk 128 works fine... and then I can operate on 80 track disks... but I cannot boot an AUTOEXEC off of an 80 track disk because setdsk 128 hasn't been run yet.

The CYA feature to set tracks checks if you have a HFDC first. Since I'm using a TIFDC only, it does not allow me to go any further.

 

To recap:

The Geneve will load SYSTEM/SYS off of the TIFDC/80-TRACK-MOD with an 80 track HFE in my Gotek drive.

SYSTEM/SYS will not load the AUTOEXEC from the 80 track HFE.

All boots fine from a 40 track HFE

I can call setdsk 128 and load goodies off of 80 track HFEs after boot is complete.

 

Since there was some literature that said CYA was about eliminating the practice of hex editing SYSTEM/SYS, is there information somewhere on the old hex-editing tricks that might work for this scenario?

When things settle down in January, I'll check the code I was working on for the next CYA release. It might have addressed the track selection issue. As for sector editing this particular setting for floppy controllers, I don't recall if that is do-able or not.