[Coco] format memory (was) Gotek floppy emulator

[Gene Heskett]

On Tuesday 16 February 2016 15:25:53 Tormod Volden wrote:

> On Tue, Feb 16, 2016 at 1:25 PM, Gene Heskett wrote:
> > On Monday 15 February 2016 20:29:02 Bill Pierce via Coco wrote:
> >>  Gene, on both my emulator and real Coco, smap shows 11k free. As I
> >> said, I can format from the cmd line, but not from within something
> >> else like the boot script from the ditro disks.
> >>
> >> One thing I've noticed is that 3.3.0 does not like older drivers.
> >> It fares better with drivers built from the same build. Are all
> >> your drivers in the 3.3.0 boot current? Or did you use some of your
> >> older custom drivers? I even formatted my 4 gig partions on my
> >> Glenside IDE with with my current boot.
> >
> > I did go down & play. I also have 11k free but its fragmented.
>
> Dear OS-9 experts, please bear with me and my lack of deep Level2
> understanding, I am in the need for a long Q&A session on this. I have
> read the "OS-9 system programmer's manual" from Microware which is the
> best piece on OS-9 internals that I have found. Are there other good
> texts, apart from reading the "source" code? "Source" in quotes,
> because a lot of it is half-commented disassembly of binaries :p
>
> OK, so you have 11k free. I suppose this is system memory (limited to
> 64KB), whereas programs can use their own 64KB user memory mapped in
> from the big pool (512KB to 2MB).
>
> > Format needs $2b70 worth of memory for its data, or 11,120 bytes.
>
> Format needs 11120 bytes of user memory, right? This is the data
> segment pointed to by U upon execution of the module, in the process'
> own memory space.
>
> I can well imagine that formatting a disk requires some system memory
> as well (for buffers etc used during system call) - and this is maybe
> the reason it goes south for you - but the 11120 bytes for format and
> the 11k free system RAM cannot be directly compared, right?
>
> I would be interested in knowing why format needs 11120 bytes (user
> memory) for doing what it does, and whether this can be reduced. But
> that is probably not very useful, since we can assume people should
> have that much of free /user/ memory when doing such tasks.
>
> The more interesting question is whether format can be made to consume
> less system memory. There is no F$ system memory requests in the
> source, only innocent I/O calls from what I can see.
>
> Off-topic question: Why is allocation bit map routines (F$AllBit and
> friends) system calls at all? They only operate on user memory, right?
>
> BTW, I just tried out format on my Level1 Dragon formatting a
> DriveWire drive, and it worked fine. It is the exact same binary as on
> Level2 systems (6809 and 6309 versions are identical too, CRC 0ABD19
> in 3.3.0).
>
> Regards,
> Tormod

Those are questions I may not have a qualified answer for until I can get 
rid of my startup file being locked forever, Tormod.  I wish I did, 
thats for sure.

Cheers, Gene Heskett
-- 
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 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>