[Coco] DW4 problems

[Gene Heskett]

On Sunday 14 October 2012 23:57:54 Aaron Wolfe did opine:

> On Sun, Oct 14, 2012 at 10:25 PM, Bob Devries <devries.bob at gmail.com> 
wrote:
> > Thanks, Robert.
> > That worked, but made no difference to the problems. I'm still getting
> > bad checksums (which seem to be ignored), and time-out, which causes
> > an ERROR #245.
> > 
> > @Aaron,
> > would the fact that I'm running this on a PAL coco3 make any
> > difference? I'm not sure what the clock2 module does in the drivewire
> > boot, or whether the clock module is in fact supposed to be for 60Hz
> > working?
> 
> I wouldn't think so, the timing for the i/o is based on instruction
> cycles.. those don't change in a 50hz system do they, same cpu crystal
> right?  Excuse my ignorance, guessing only the video stuff changes but
> what do I know :)
> 
> What kind of hard drive are you copying from?  I have only the
> superIDE here, and tests with it seem to work OK but I need to do some
> more.  I know Gene's hdd is an uncommon one...  wondering if maybe the
> DW driver and the hdd driver don't get along in your cases, some
> timing thing that only rears its head under stressful constant use?
> 
> Given enough info and time I'm sure we can sort this out and make
> everything work properly, but I'm having a hard time getting a test
> case where I can recreate the issue put together so far.
 
So am I.  I hate to have to shotgun every piece in the USB chain just to 
rule it out as that is at least $150 worth of hardware.

As for my HD setup being an odd one, so its scsi, on a TC^3 controller, 
shouldn't be a big deal.

I can do a megaread from either of them in exactly the same time as myram 
can do a megaread, around 11.5 seconds.  So far I haven't seen any figures 
on the IDE interfaces that can match that, the last ones quoted on this 
list were about 18 seconds.  These drives are so fast (20Mb/sec or more) 
that megaread is basically testing how fast it can move a megabyte from one 
location in ram to a different one, so why does the IDE stuff crawl in 
comparison?  I don't know.

The last time I tried to backup one of these drives using my basic09 
version of dd, it got to 68 megabytes according to drivewire before it 
timed out.

But when I looked at the disk image with ls -l, the image on the disk was 
only 25 bytes long, and could not be remounted by dw once unloaded.  So dw 
never even wrote the first sector of about 132,000 sectors it claimed to 
have written at that point.  That image was a copy of another file I'm 
still using, renamed, about 4Mb in size, and my dd was supposed to 
completely overwrite it from LSN0 on, so that I would wind up with a 
verbatum copy of that disk as a 1 Gb file on my disk.

Now, this particular kernel seems to have a scheduler problem, and its 
entirely possible in my mind that its poor performance could cause some 
data loss from a usb stream.  The way to answer that is probably for me to 
copy over one of the lots newer kernels from my old pclos install, which is 
on a different drive & reboot to it.  Those were SMP, PAE and BFS enabled 
and this machine ran a lot snappier.

I may see if I can do that tomorrow.

In the meantime Aaron, I've did the display 1b etc stuff you were doing in 
the video, to /n5, then started a shell on /n5, so it looks like this in a 
proc report:
{t2|08}/DD/MAXTOR/CMDSINEVERUSE:proc            

 ID Prnt User Pty  Age  Tsk  Status  Signal   Module    I/O Paths 
___ ____ ____ ___  ___  ___  _______ __  __  _________ __________________
  1   0    0  255  255   00  sTimOut  0  00  System    <Term >Term >>Term 
  2   1    0  128  128   00  s        0  00  Shell     <Term >Term >>Term 
  3   2    0  128  128   00  s        0  00  Shell     <N5   >N5   >>N5   
  4   8    0  128  128   02  s        0  00  Proc      <t2   >t2   >>t2   
  5   0    0  128  131   00  s        0  00  Shell     <W4   >W4   >>W4   
  6   0    0  128  131   00  s        0  00  Shell     <W1   >W1   >>W1   
  7   0    0  128  131   00  s        0  00  Shell     <W2   >W2   >>W2   
  8   0    0  128  131   00  s        0  00  Shell     <t2   >t2   >>t2   
  9   0    0  128  131   00  s        0  00  inetd     <W3   >W3   >>W3

But there seems to be no way I can make the gui give me the extra header 
line with the N tabs that you show coming and going automatically.

I've even tried to hook ZTerm to n5 but the only clue is a logged line that 
said dw didn't know what to do with the shell's signon banner.

So how does that work?  The video had the dw command line at the bottom of 
the screen clipped off.

Cheers, Gene
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