NEW USB Host Controller via ACSI

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czietz
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Re: NEW USB Host Controller via ACSI

Postby czietz » Sun Sep 24, 2017 8:09 am

Atari GEMDOS FAT implementation has some restrictions -- the most notable being that on TOS versions 1-3 a cluster must not be bigger than 16384 bytes. (Bad choice of a signed int16 to hold the cluster size.) Other limits are described in the following document, section 9.3:
http://info-coach.fr/atari/documents/_m ... _Guide.pdf

HDDRUTIL when partitioning a disk will try to work with these limitations when you select to create a TOS-compatible partition. Partitions created by other tools (like on the PC or Mac) will obviously not adhere to the limits, i.e. they might not work even if a partition is smaller than the maximum size of 512 MiB supported by TOS 1.04 - 3.06.

Enter BigDOS: it replaces GEMDOS and thus allows accessing bigger partitions and partitions created by non-Atari-aware tools. BigDOS -- though being 20 years old -- is by no means obsolete, even with the newest versions of HDDRIVER. See its FAQ: http://hddriver.seimet.de/en/faq.html
Imho it would be a nice improvement to HDDRIVER if Uwe Seimet developed a BigDOS replacement. Or the BigDOS author could be persuaded to open-source his work.

alanh
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Re: NEW USB Host Controller via ACSI

Postby alanh » Sun Sep 24, 2017 9:01 am

BigDOS only allows FAT16 partitions to be used, these are not TOS partitions.

You need to create the type field as $06 to use them with BigDOS, but they can be up to 2GB.

BigDOS also disables <32MB partitions, so make sure any partition is bigger than that.
Falcon CT60, Falcon CT63 x2, TT x3, MegaST x2, MegaSTE x2, STFM x2, STE x2, STacy, STBook, (Dead) Hades 060, Milan 060, T40.

czietz
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Re: NEW USB Host Controller via ACSI

Postby czietz » Sun Sep 24, 2017 10:02 am

alanh wrote:BigDOS only allows FAT16 partitions to be used, these are not TOS partitions.
You need to create the type field as $06 to use them with BigDOS, but they can be up to 2GB.
BigDOS also disables <32MB partitions, so make sure any partition is bigger than that.


Well, it's certainly good that my BigDOS installation isn't aware of your post. :D
What I'm trying to say: I have no problems with either TOS partitions (like created by AHDI's HDX) nor with <32 MB (type "GEM") partitions together with BigDOS. Nothing is disabled or unusable.

May I ask where you got the information above?

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Fujiyama
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Re: NEW USB Host Controller via ACSI

Postby Fujiyama » Sun Sep 24, 2017 12:43 pm

alanh wrote:BigDOS only allows FAT16 partitions to be used, these are not TOS partitions.

You need to create the type field as $06 to use them with BigDOS, but they can be up to 2GB.

BigDOS also disables <32MB partitions, so make sure any partition is bigger than that.


Aha! That explains why my CF-card boot partition (drive C) didn't appear when I had BigDOS in the AUTO folder! I believe drive C is set to 15 MB in order to not exceed the 16 MB limit in TOS (I'm a little confused about that as well because of conflicting information).

So if I use BigDOS (by putting it (first, according to its docs) in the AUTO folder) I first need to repartition my CF card which contains the boot partition as well so that all partitions are between 32 MB and 2 GB or...... leave things as they are, not use BigDOS but also not be able to use more than 512 MB on my USB flash drive (or if I like a more "messy" setup (IMHO of course) partition up the 8 GB drive into multiple 512 MB partitions)?

In any case it's fantastic to be able to have a cross-platform compatible removable media which is fast, silent, compact and huge. Even high density (1.44 MB) floppies bite the dust in comparison. So thanks for all your efforts in creating both the Unicorn and MonSTer, Alanh! :thumbs: :-D

Czietz: So you've also got a boot partition which is smaller than 32 MB? Also 16 MB or less like mine?
And BigDOS doesn't make it inaccesible when you boot with it in the AUTO folder? Which TOS version are you using, and is this together with HDdriver (in case yes -which version)?
Mega STe | MonSTer with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESSC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

czietz
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Re: NEW USB Host Controller via ACSI

Postby czietz » Sun Sep 24, 2017 1:44 pm

Fujiyama wrote:Czietz: So you've also got a boot partition which is smaller than 32 MB? Also 16 MB or less like mine?
And BigDOS doesn't make it inaccesible when you boot with it in the AUTO folder? Which TOS version are you using, and is this together with HDdriver (in case yes -which version)?


Like I said. I haven't had any problems with BigDOS with partitions smaller than 32 MB, be it with Atari-style partitions, be it with MS-DOS-style partitions. Neither with TOS 1.04 nor with TOS 2.06. I don't use HDDRIVER, though.

If you don't believe me, attached is a HD image for Hatari (mount as ACSI image within Hatari) with a boot partition of about 14 MB and a second partition of about 17 MB. It will boot from HD, load BigDOS from C:\AUTO and still all partitions will be accessible. No problems whatsoever!

Fujiyama wrote:I believe drive C is set to 15 MB in order to not exceed the 16 MB limit in TOS (I'm a little confused about that as well because of conflicting information).


Read the PDF document I posted: About the boot partition it says: "Contrary to widely spread belief, the boot partition (usually the first partition on disk) can be a big partition (BGM) and therefore can use the maximum size supported by the TOS (For example 512MB for 1.04 ≤ TOS < 4.x). The actual limitation to 32MB (GEM) for the boot partition does not come from TOS/GEMDOS file system but from some hard disk driver. Only very old hard disk driver like SCSITools and AHDI hard disk driver exhibit this limitation."
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alanh
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Re: NEW USB Host Controller via ACSI

Postby alanh » Sun Sep 24, 2017 5:02 pm

czietz wrote:
alanh wrote:BigDOS only allows FAT16 partitions to be used, these are not TOS partitions.
You need to create the type field as $06 to use them with BigDOS, but they can be up to 2GB.
BigDOS also disables <32MB partitions, so make sure any partition is bigger than that.


Well, it's certainly good that my BigDOS installation isn't aware of your post. :D
What I'm trying to say: I have no problems with either TOS partitions (like created by AHDI's HDX) nor with <32 MB (type "GEM") partitions together with BigDOS. Nothing is disabled or unusable.

May I ask where you got the information above?


http://atari.8bitchip.info/ASThdFAQ.html
http://www.atari-forum.com/viewtopic.php?t=18462
Falcon CT60, Falcon CT63 x2, TT x3, MegaST x2, MegaSTE x2, STFM x2, STE x2, STacy, STBook, (Dead) Hades 060, Milan 060, T40.

czietz
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Re: NEW USB Host Controller via ACSI

Postby czietz » Sun Sep 24, 2017 7:36 pm



Only that the sentence "[BigDOS] disables partitions under 32MB" is wrong at least a general statement as my own experience and the Hatari disk image that I posted show. Maybe this happens under some special circumstances ... which I would be interested in knowing.

PS: We can move this to a separate thread if you like since this has nothing to do anymore with the Unicorn.


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