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XF551 Hyper FX MOD

53 replies to this topic

#51 1050 ONLINE  



  • 961 posts

Posted Sun Jan 14, 2018 4:39 AM

I've tried every mode and had troubles setting the mode
too. Literally at my wits end and she won't boot the
360K XF-551 disk with DOS.SYS on the backside. May have
been a flaky eprom doing most of my troubles.

But thanks for the run down on how to do it again and
I will try it again. But my takeaway is that I'm having
a lot of trouble with this and it shouldn't be so much

#52 Nezgar OFFLINE  



  • 611 posts
  • Location:Regina SK Canada

Posted Sun Jan 14, 2018 10:35 AM

I read on another thread that the double sided internal PBI drives in a 1450XLD would address side 2 as drive 2, and also write the data 'backwards' in a way that was compatible in a single sided drive when flipped.

Great ingenuity there that never made it out there!

#53 _The Doctor__ OFFLINE  

_The Doctor__

    River Patroller

  • 3,958 posts
  • Location:10-0-11-00:02

Posted Sun Jan 14, 2018 9:38 PM

One of the ideas for the 1450 drive was to buffer the whole track and write the data backwards from the buffer without switching rotation, since almost all copy protection was on disk intended to be drive1, this would make access faster on the extra drives and maintained compatibility across all the drives... copy protected disks worked fine on drive 1 and 3, and drives 2 and 4 could still read and write disk understood by all..... the buffer was key... without it...way too big of a performance hit.....

#54 StefanD OFFLINE  


    Star Raider

  • 57 posts

Posted Wed Jan 17, 2018 1:24 PM



I'm the author of the Hyper XF ROM.


There is only one version of Hyper XF (1.0) and there are no known bugs. Unfortunaly, I haven't ever written any special software for the Hyper XF and don't plan to do it. Following software is missing:

- Fast sector copier: should analyze track 0 with command g and then use the found track layout to read the other tracks fast (by using the appropriate sector interleave)
- Read/Copy ST/IBM 360K/720K disks: by using command t
- Track analyzer: by using command g (and perhaps t)
- Copy protected disks: with commands g, t and e


Since everybody uses SIO2USB/SIO2SD/SDrive today, I would say, a Track analyzer would be the most interesting software - and it's not very difficult since command g does most of the needed work. If you want to write software for the Hyper XF, I would explain the commands in detail. Here is a short overview of the modified and new commands:


S: Supports density check options
W: Writes always without verify (like P does)
?: Get Ultra Speed Pokey divisor (=9)
Space: Format background. Returns immediately from the SIO call, before formatting starts (same as in Speedy ROM)
f: Formats with predefined sector numbers (some other ROMs have this)
c: Configure mode. Sets the operation mode (like the Hyper XF menu does). Default is X (same as standard XF551)
e: Extended format. Formats one track with an arbitrary format (sector numbers, gaps, error sectors can be defined)
g: Get track info: Analyzes one track. The result can be used by command e to duplicate a track layout exactly
t: Read error sector. Reads a Single/Medium error sector fast (without retry) or one half of a 512 byte sector.
u: Update error sector. Writes an error sector in Single or Medium Density


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