[Coco] NitrOS9 question

Dave Philipsen dave at davebiz.com
Sat Oct 7 21:59:20 EDT 2017


I can kind of understand basically what’s going on.  I *think* an unused block of RAM is used by the kernel to do certain chores involved in copying data from one place to another perhaps. The unused block gets mapped into the $A000-BFFF MMU block which is assumed to contain system modules which are basically read-only.  When the original block is mapped out temporarily, it turns out that because of the small size boot file it wasn’t holding system modules after all.  It was containing some important data for the kernel which is dynamically aloocated.  So now the kernel, while processing a particular function, goes to access that memory but another block is temporarily mapped in there.  I could be off on exactly what is happening there but that’s kind of the idea I got when reading the comments. Whoever wrote the code made an assumption that that particular block would always be in use for a particular sort of thing.  When they originally designed Level 2 perhaps they never imagined anyone trimming down a boot file to be so small and they never imagined anyone would pull the graphics functions out (CoWin and/or VTIO modules).

In fact, was Level 2 ever officially ported to anything besides the CoCo 3 by Microware?

Dave

> On Oct 7, 2017, at 6:21 PM, David Ladd <davidwladd at gmail.com> wrote:
> 
> Dave,
> 
> That is good to know.
> 
> I know my test boot disk I was using was on the CoCoSDC, but I am using the
> standard REL, KRN, and Boot modules.  I know that if I stay above $4200 on
> my OS9Boot file it works fine, but if I go under $4200 for size it crashes.
> 
> Interesting the modules used to boot on the SD card crashes below $4400.
> We have some really freaky stuff going on here :P
> 
> 
> +-----------------------------------------------------------------------+
> | David Ladd a.k.a. PacoOtaktay a.k.a. Drencor                          |
> | YouTube: http://www.youtube.com/user/PacoOtaktay                      |
> | YouTube Gaming Live: https://gaming.youtube.com/user/PacoOtaktay/live |
> | Websites: http://dwladd.com     &     http://www.theterrorzone.com    |
> | G+:  https://plus.google.com/113262444659438038657                    |
> | G+:  https://plus.google.com/+DavidLaddPacoOtaktay                    |
> |                                                                       |
> | Do you have your CoCo 3 yet?                                          |
> +-----------------------------------------------------------------------+
> 
> 
>> On Sat, Oct 7, 2017 at 5:28 PM, Dave Philipsen <dave at davebiz.com> wrote:
>> 
>> I just now read the notes. Apparently there were some comments made over
>> six years ago but no action was taken on it. And in reality, it's probably
>> not a problem most people would ever see.  And even for me it's not going
>> to be a big deal now that I know about it and how to avoid it. I have a
>> basic understanding of why it's happening and I did see some references to
>> the use of the FFA5 block of the MMU in the kernel source code as a sort of
>> temporary area for manipulating data.
>> 
>> 
>> Dave
>> 
>> 
>> 
>>> On 10/7/2017 5:05 PM, Tormod Volden wrote:
>>> 
>>> Hi guys,
>>> 
>>> Sorry I haven't read the whole thread, but the issue with too small
>>> OS9BOOT files is documented in the bug tracker, with explanation IIRC.
>>> 
>>> Regards,
>>> Tormod
>>> 
>>> 
>>>> On Sat, Oct 7, 2017 at 9:02 AM, Dave Philipsen <dave at davebiz.com> wrote:
>>>> 
>>>> Very interesting, David.  Thanks for the quick update.
>>>> 
>>>> Dave
>>>> 
>>>>> On Oct 6, 2017, at 11:40 PM, David Ladd <davidwladd at gmail.com> wrote:
>>>>> 
>>>>> Dave,
>>>>> 
>>>>> To fix my booting issue I just added sysgo into the OS9Boot file to
>>>>> fill up
>>>>> some space (*shrug*) and works fine.  I know it doesn't make any sense,
>>>>> but
>>>>> maybe Robert, Curtis, Bill, or Bill can give some feedback on this.
>>>>> 
>>>>> +-----------------------------------------------------------
>>>>> ------------+
>>>>> | David Ladd a.k.a. PacoOtaktay a.k.a. Drencor
>>>>> |
>>>>> | YouTube: http://www.youtube.com/user/PacoOtaktay
>>>>>  |
>>>>> | YouTube Gaming Live: https://gaming.youtube.com/user/PacoOtaktay/live
>>>>> |
>>>>> | Websites: http://dwladd.com     &     http://www.theterrorzone.com
>>>>>  |
>>>>> | G+:  https://plus.google.com/113262444659438038657
>>>>>  |
>>>>> | G+:  https://plus.google.com/+DavidLaddPacoOtaktay
>>>>>  |
>>>>> |
>>>>> |
>>>>> | Do you have your CoCo 3 yet?
>>>>> |
>>>>> +-----------------------------------------------------------
>>>>> ------------+
>>>>> 
>>>>> 
>>>>> On Fri, Oct 6, 2017 at 8:26 PM, Dave Philipsen <dave at davebiz.com>
>>>>>> wrote:
>>>>>> 
>>>>>> Ok, so it’s larger than $4401.  I’d be curious to see what would
>>>>>> happen if
>>>>>> you removed rb1773, d0, d1, and d2 from the bootfile.  That would
>>>>>> probably
>>>>>> get it down below $4401 in size.
>>>>>> 
>>>>>> Dave
>>>>>> 
>>>>>>> On Oct 6, 2017, at 8:19 PM, David Ladd <davidwladd at gmail.com> wrote:
>>>>>>> 
>>>>>>> Dave,
>>>>>>> 
>>>>>>> Here is the directory from the root:
>>>>>>> 
>>>>>>> {Term|02}/DD:dir -e
>>>>>>> 
>>>>>>> Directory of .  2017/09/28 23:04
>>>>>>> 
>>>>>>> Owner  Last modified   Attributes Sector Bytecount Name
>>>>>>> ----- ---------------- ---------- ------ --------- ----
>>>>>>> 0  2017/10/06 15:49  ------wr      13      485F OS9Boot
>>>>>>> 0  2017/10/06 15:49  d-ewrewr      5D       B20 CMDS
>>>>>>> 0  2017/10/06 15:49  d-ewrewr      66       1C0 SYS
>>>>>>> 0  2017/10/06 15:49  d-ewrewr      6F       100 DEFS
>>>>>>> 0  2017/09/28 21:12  ----r-wr      78       F00 ccbkrn
>>>>>>> 0  2017/09/28 21:12  --e-rewr      88       1FF sysgo
>>>>>>> 0  2017/09/28 21:01  ----r-wr     62D        F9 startup
>>>>>>> 0  2017/10/06 15:49  d-ewrewr     62F        60 NITROS9
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> +-----------------------------------------------------------
>>>>>>> 
>>>>>> ------------+
>>>>>> 
>>>>>>> | David Ladd a.k.a. PacoOtaktay a.k.a. Drencor
>>>>>>>  |
>>>>>>> | YouTube: http://www.youtube.com/user/PacoOtaktay
>>>>>>> 
>>>>>> |
>>>>>> 
>>>>>>> | YouTube Gaming Live: https://gaming.youtube.com/use
>>>>>>> r/PacoOtaktay/live
>>>>>>> 
>>>>>> |
>>>>>> 
>>>>>>> | Websites: http://dwladd.com     &     http://www.theterrorzone.com
>>>>>>> 
>>>>>> |
>>>>>> 
>>>>>>> | G+:  https://plus.google.com/113262444659438038657
>>>>>>> 
>>>>>> |
>>>>>> 
>>>>>>> | G+:  https://plus.google.com/+DavidLaddPacoOtaktay
>>>>>>> 
>>>>>> |
>>>>>> 
>>>>>>> |
>>>>>>>   |
>>>>>>> | Do you have your CoCo 3 yet?
>>>>>>>  |
>>>>>>> +-----------------------------------------------------------
>>>>>>> 
>>>>>> ------------+
>>>>>> 
>>>>>>> 
>>>>>>> On Fri, Oct 6, 2017 at 7:43 PM, Dave Philipsen <dave at davebiz.com>
>>>>>>>> 
>>>>>>> wrote:
>>>>>> 
>>>>>>> Ok, so how big is the bootfile?
>>>>>>>> 
>>>>>>>> Dave
>>>>>>>> 
>>>>>>>>> On Oct 6, 2017, at 4:15 PM, David Ladd <davidwladd at gmail.com> wrote:
>>>>>>>>> 
>>>>>>>>> Dave,
>>>>>>>>> 
>>>>>>>>> Since I can't test this on a CoCo3FPGA right now I did finally get
>>>>>>>>> my
>>>>>>>>> Deluxe RS232 Pak working.  I modified the make files for the
>>>>>>>>> NitrOS-9
>>>>>>>>> project and made myself a CoCoSDC headless that uses the sc6551
>>>>>>>>> driver
>>>>>>>>> 
>>>>>>>> and
>>>>>>>> 
>>>>>>>>> term modules.  Here is my short ident of my OS9Boot file.  I tested
>>>>>>>>> it
>>>>>>>>> 
>>>>>>>> and
>>>>>>>> 
>>>>>>>>> it does work and with the standard Shell+ as well.
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> {Term|02}/DD:ident os9boot -s
>>>>>>>>> 19 $C0 $FA063B . KrnP2
>>>>>>>>> 13 $C1 $FB10BD . IOMan
>>>>>>>>> 1 $C0 $9D910E . Init
>>>>>>>>> 37 $D1 $245E32 . RBF
>>>>>>>>> 2 $E1 $84C07C . RBSuper
>>>>>>>>> 22 $21 $230904 . llcocosdc
>>>>>>>>> 82 $F1 $DB0F90 . SD0
>>>>>>>>> 82 $F1 $081F95 . SD1
>>>>>>>>> 82 $F1 $F8621C . DD
>>>>>>>>> 1 $E1 $A4EB50 . rb1773
>>>>>>>>> 82 $F1 $045CD6 . D0
>>>>>>>>> 82 $F1 $803FAD . D1
>>>>>>>>> 82 $F1 $8C9A43 . D2
>>>>>>>>> 18 $D1 $55C62E . SCF
>>>>>>>>> 10 $E1 $67C110 . sc6551
>>>>>>>>> 83 $F1 $64212E . Term
>>>>>>>>> 5 $D1 $6F9717 . PipeMan
>>>>>>>>> 2 $E1 $895C5F . Piper
>>>>>>>>> 80 $F1 $D512FB . Pipe
>>>>>>>>> 9 $C1 $9A36A3 . Clock
>>>>>>>>> 1 $21 $5833D2 . Clock2
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> +-----------------------------------------------------------
>>>>>>>>> 
>>>>>>>> ------------+
>>>>>>>> 
>>>>>>>>> | David Ladd a.k.a. PacoOtaktay a.k.a. Drencor
>>>>>>>>> 
>>>>>>>>  |
>>>>>> 
>>>>>>> | YouTube: http://www.youtube.com/user/PacoOtaktay
>>>>>>>>> 
>>>>>>>> |
>>>>>>>> 
>>>>>>>>> | YouTube Gaming Live: https://gaming.youtube.com/
>>>>>>>>> 
>>>>>>>> user/PacoOtaktay/live
>>>>>> 
>>>>>>> |
>>>>>>>> 
>>>>>>>>> | Websites: http://dwladd.com     &
>>>>>>>>> http://www.theterrorzone.com
>>>>>>>>> 
>>>>>>>> |
>>>>>>>> 
>>>>>>>>> | G+:  https://plus.google.com/113262444659438038657
>>>>>>>>> 
>>>>>>>> |
>>>>>>>> 
>>>>>>>>> | G+:  https://plus.google.com/+DavidLaddPacoOtaktay
>>>>>>>>> 
>>>>>>>> |
>>>>>>>> 
>>>>>>>>> |
>>>>>>>>> 
>>>>>>>> |
>>>>>> 
>>>>>>> | Do you have your CoCo 3 yet?
>>>>>>>>> 
>>>>>>>>  |
>>>>>> 
>>>>>>> +-----------------------------------------------------------
>>>>>>>>> 
>>>>>>>> ------------+
>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> On Fri, Oct 6, 2017 at 8:06 AM, Dave Philipsen <dave at davebiz.com>
>>>>>>>>>> 
>>>>>>>>> wrote:
>>>>>>>> 
>>>>>>>>> I would like to do some experiments with this on a real CoCo 3, too.
>>>>>>>>>> 
>>>>>>>>> I'm
>>>>>>>> 
>>>>>>>>> using the CoCo3FPGA right now.  It's much easier for me to test
>>>>>>>>>> things
>>>>>>>>>> 
>>>>>>>>> on
>>>>>>>> 
>>>>>>>>> this platform because I have the ability to boot with an alternate
>>>>>>>>>> 
>>>>>>>>> bootfile
>>>>>>>> 
>>>>>>>>> just by holding down the ALT key while booting.  I can make changes
>>>>>>>>>> to
>>>>>>>>>> 
>>>>>>>>> the
>>>>>>>> 
>>>>>>>>> OS9Boot.1 file while still retaining the original OS9Boot file.
>>>>>>>>>> Also,
>>>>>>>>>> because of Brett's bootloader, I don't have to do anything special
>>>>>>>>>> to
>>>>>>>>>> generate the bootfile.  I just merge all of the modules needed and
>>>>>>>>>> the
>>>>>>>>>> bootloader will load it no matter if it's fragmented or where it
>>>>>>>>>> 
>>>>>>>>> resides on
>>>>>>>> 
>>>>>>>>> the disk structure.
>>>>>>>>>> 
>>>>>>>>>> Dave
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>>> On 10/6/2017 7:50 AM, Aaron Wolfe wrote:
>>>>>>>>>>> 
>>>>>>>>>>> We ran into the same issue when creating the headless Drivewire
>>>>>>>>>>> disks
>>>>>>>>>>> 
>>>>>>>>>> some
>>>>>>>> 
>>>>>>>>> years ago.  If the boot file became too small, things went badly.
>>>>>>>>>>> 
>>>>>>>>>>> Unfortunately Boisy solved this in our case so I can't give you
>>>>>>>>>>> 
>>>>>>>>>> specifics.
>>>>>>>> 
>>>>>>>>> Not sure if he still monitors this list, fairly sure he intended to
>>>>>>>>>>> 
>>>>>>>>>> patch
>>>>>>>> 
>>>>>>>>> the nitros9 source to correct the bug. Perhaps the fix got lost or
>>>>>>>>>>> 
>>>>>>>>>> was
>>>>>> 
>>>>>>> not
>>>>>>>> 
>>>>>>>>> comprehensive.  In any case, I can confirm a third case where small
>>>>>>>>>>> 
>>>>>>>>>> boot
>>>>>>>> 
>>>>>>>>> file became an issue in itself.
>>>>>>>>>>> 
>>>>>>>>>>> -Aaron
>>>>>>>>>>> 
>>>>>>>>>>> On Oct 6, 2017 8:35 AM, "Neal Crook" <foofoobedoo at gmail.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>> 
>>>>>>>>>>> In my mc09 l2 development I found a bug where a too - small
>>>>>>>>>>> bootfile
>>>>>>>>>>> 
>>>>>>>>>> would
>>>>>>>> 
>>>>>>>>> hang. Padding it fixed the problem. I will look out the details over
>>>>>>>>>>> 
>>>>>>>>>> the
>>>>>>>> 
>>>>>>>>> weekend and let you know, so we can see if our experiences tally. It
>>>>>>>>>>> 
>>>>>>>>>> would
>>>>>>>> 
>>>>>>>>> be good to know that it was a generic problem and not specific to my
>>>>>>>>>>> target
>>>>>>>>>>> hardware. I spent quite a lot of time in emulation trying to
>>>>>>>>>>> track it
>>>>>>>>>>> 
>>>>>>>>>> down
>>>>>>>> 
>>>>>>>>> without success
>>>>>>>>>>> 
>>>>>>>>>>> Neal
>>>>>>>>>>> 
>>>>>>>>>>> On 6 Oct 2017 12:40, "Dave Philipsen" <dave at davebiz.com> wrote:
>>>>>>>>>>> 
>>>>>>>>>>> Haha!  That doesn't work either.  But as soon as I re-assemble
>>>>>>>>>>> Term
>>>>>>>>>>> 
>>>>>>>>>> with
>>>>>>>> 
>>>>>>>>> 265 extra bytes in it, it boots just fine.  So it really does appear
>>>>>>>>>>> 
>>>>>>>>>> to be
>>>>>>>> 
>>>>>>>>> an issue with size and not order.
>>>>>>>>>>> 
>>>>>>>>>> --
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