[Coco] format memory (was) Gotek floppy emulator

[Bill Nobel]

If memory serves me correct Tormond.  Format uses the user space for the 11120 bytes for the Track being formatted.  Format uses this memory as the Track definition (including pre and post track stuff) this data is written to the physical track on the drive.  It is not just the sector itself.  The only thing that should come out of the system space for memory is the path and device table entries.

Bill Nobel

> On Feb 16, 2016, at 2:25 PM, Tormod Volden <lists.tormod at gmail.com> 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
> 
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