Re: [Simh] 8" Floppy disk image getting HALT error

[Timothe Litt]

On 11-Jul-17 18:02, Johnny Billquist wrote:
> On 2017-07-11 21:09, Timothe Litt wrote:
>> VMS mount /over=id /foreign is the quickest way to identify files-11 and
>> RT disks.  FILES-11 can be read directly; use EXCHANGE for RT-11.  Once
>> you have the disk mounted on VMS, you can network it to wherever you
>> like.
>
> Similar story if you have RSX. I might have forgotten a thing or two
> about VMS here, but I would have thought /OVER=ID/FOREIGN would not
> then let you access the disk in the direct way if it is Files-11.
I was suggesting the easiest way to IDENTIFY the media.  /FOREIGN will
dump the filesystem type when it looks for a HOM block.  Once you know
that, you use the appropriate command / utility to access that type.

To access FILES-11 on VMS, you don't use /FOREIGN, just mount (though
/over=id will allow a private mount without knowing the volume label.)

MOUNT and EXCHANGE details are available from HELP and the manuals.

VMS has, arguably, the most filesystem support and tools for this.  But
OS choice is a religion.  Use whatever you believe in & have available;
there is no point in arguing religion.

Of course, if the OP is more interested in the result than the process,
he can probably get one of us to extract the one file for him...



smime.p7s
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Re: [Simh] 8" Floppy disk image getting HALT error

[Johnny Billquist]

Hi, Ragge, :-)

On 2017-07-11 23:50, Anders Magnusson wrote:

Den 2017-07-11 kl. 14:29, skrev Johnny Billquist:


To sum things up. You can probably ignore all the questions about if
this really is some DEC floppy, what kind of format it has, and so on.
If kryoflux managed to extract data that looks valid with RX02
parameter settings, then I'd say we can be sure it is an RX02 disk.
And this format was unique to DEC, so it can't be anything else.


Nitpicking:  Sintran had the same format (F-F 12 IIRC) so DEC floppies
could be used by Sintran and vice versa.
The RX02 floppies were pre-formatted by DEC and were quite expensive,
but any floppy could be formatted using Sintran and then used on a VAX
for example :-)


Are you confusing the RX01/RX02 with the RX50 now?
The RX01 is a bog standard IBM format SSSD floppy.
The RX02 is the same as an RX01. DEC just flips a bit in the header of 
each sector, and write the data in double density. So you can always 
easily format back and forth between RX01 and RX02 in the floppies, and 
anyone could do it.


The RX50 on the other hand was preformatted, and in a format that (I 
thought) noone else used. So DEC really had a captive market for that one.


I've used plenty of IBM 8" floppies in RX01 drives... Never had an RX02 
myself, so I could not do the reformatting for that. But look inside any 
DEC OS, and you'll find the command to reformat RX01 as RX02 and back.


Johnny

--
Johnny Billquist  || "I'm on a bus
  ||  on a psychedelic trip
email: b...@softjar.se ||  Reading murder books
pdp is alive! ||  tryin' to stay hip" - B. Idol
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Re: [Simh] 8" Floppy disk image getting HALT error

[Johnny Billquist]

On 2017-07-11 21:09, Timothe Litt wrote:

VMS mount /over=id /foreign is the quickest way to identify files-11 and
RT disks.  FILES-11 can be read directly; use EXCHANGE for RT-11.  Once
you have the disk mounted on VMS, you can network it to wherever you like.


Similar story if you have RSX. I might have forgotten a thing or two 
about VMS here, but I would have thought /OVER=ID/FOREIGN would not then 
let you access the disk in the direct way if it is Files-11.



If you insist on doing things the hard way, there is low-level detail to
worry about.

The first  track on DEC 8" floppies is reserved for boot (but not used)
in the standard RX01/2 formats.  It's not used by any DEC OS.  Not even
for booting (the DEC boot block is the first LBN following the reserved
track.)

Both are 77 tracks, 1 sided, 26 sectors/track.  The rx01 is 128
bytes/sector; the rx02 256.  So an RX01 image will be about 251KB, an
RX02 about 501KB.


Which then makes sense for data to start at track 26.


Logical blocks are 512 bytes; meaning that an LBN consists of 4 or 2
physical sectors.  The physical sectors are interleaved.  If you have a
physical dump of the disk (and your tools haven't outsmarted you), the
easiest thing to do is to de-interleave it.

Use the attached utility, which documents the format & will
interleave/deinterleave a floppy image using the usual interleave rules.

19D0(16) is close to 26 * 256 (short by 48 bytes), so I'd guess you have
an rx02 and are seeing the empty boot track.  (Although not guaranteed,
the track was usually written with all zeroes).


I think Walked was a little careless in his conversion. He said bytes 
0-6655, which actually turns out to be 01A0, or exactly where track 1 
starts.



The 48 bytes may be left over from formatting, or an artifact of how
you're reading the medium.  Or an indication that your recovery dropped
something.  Hopefully it checks the CRCs..


Or just a conversion error. :-)


The E5 is probably left over from formatting.  I think it was part of
the sync pattern, and that the formatter wrote

If you see 8-bit data, it's probably RT11 or Files-11.  These are
self-identifying - block 1 (the second block) will have a filesystem
name in starting at byte 760(8).  Will be DECFILE11A for ODS1 or
DECFILE11B for ODS2, DECRT11A for RT11.  RSTS is also possible - I don't
remember it's code, probably DECRSTS11A.  Given that, data
(deinterleaved), humans can easily tell what you have.


Unfortunately it's not that easy.
Files-11 do indeed have that identifier in block 1. RT-11 however, might 
not. There is no requirement and no checking, and depending on what 
version, and what tool, you might be lucky and find such a string there, 
but the absence don't mean anything.
VMS Exchange helpfully enough actually writes "DECVMSEXCHNG" there. 
(cut-and-pasted from a dump right here and now)
FLX (under RSX) do not write anything at all when you initialize the 
disk with an RT-11 file structure.


I don't have any RSTS/E disk images to quickly peek into.

But with some detective work, you can still figure out if it is an RT-11 
volume.


But the fact that the dump seem to get directly to document data without 
anything at all suggest that there isn't any file structure at all on 
the disk.



RT11 files are contiguous, so recovery is easy.  FILES-11 files can be,
but probably aren't.  You have to read mapping pointers.  There are
tools that will do that (one of these daze I do intend to release mine.)

But it's much easier to just run EXCHANGE and say "COPY" by filename :-)


Indeed. Seems unneccesary work to write a tool to parse that out when 
tools already exist. You can do it in VMS, or RSX, RSTS/E or Ultrix, 
without having to write any code.



As for WPS-8  - yes, it's packed into 12 bits - but it's also encoded (I
vaguely remember it as a 6-bit code with shift & formatting - but I'd
have to look up the code I wrote to translate it.)  In any case, it
would not look like text to a "modern" filesystem.


Yeah. I think we can exclude WPS from likely formats.

Johnny



Have fun.

On 11-Jul-17 13:26, Walker Sampson wrote:

Hi everyone,

Many thanks for this feedback. A fair amount to chew on here. I’ve sent a 
request to the donor to share the disk image, if I get a positive I’ll be happy 
to throw up a Dropbox link to it for others to examine.

This may mean a problematic read of the disk itself, but addresses 0 – 
019D0 are all zeroed out, or about bytes 0 – 6655.

Data begins at byte 6657, and that is the document I mentioned. Last byte of 
the document is 73080 and then just blocks of either zero or E5E5E5E5 till the 
end of the disk.

To Paul’s point of mounting a RK05 drive – which drive should I be mounting here, 
assuming it is the RX02 disk it seems to be? “AT RX01 ” still gets 
a HALT error. Of course, as you all point out, perhaps this isn’t a bootable disk, 
period. “SH RX01” gives “RX1, 256KB, attached to test-decrx01.img, write enabled”

FYI as well, on a 

Re: [Simh] 8" Floppy disk image getting HALT error

[Anders Magnusson]

Den 2017-07-11 kl. 14:29, skrev Johnny Billquist:


To sum things up. You can probably ignore all the questions about if 
this really is some DEC floppy, what kind of format it has, and so on. 
If kryoflux managed to extract data that looks valid with RX02 
parameter settings, then I'd say we can be sure it is an RX02 disk. 
And this format was unique to DEC, so it can't be anything else.


Nitpicking:  Sintran had the same format (F-F 12 IIRC) so DEC floppies 
could be used by Sintran and vice versa.
The RX02 floppies were pre-formatted by DEC and were quite expensive, 
but any floppy could be formatted using Sintran and then used on a VAX 
for example :-)


-- R
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Re: [Simh] 8" Floppy disk image getting HALT error

[Johnny Billquist]

Timothe Litt brought up that track 0 is probably not actually used.
I was just trying to remember that one myself, so there is probably 
your explanation for all the zeroes in the beginning.


Size looks good. An RX01 should be about 128Kbyte, while an RX02 should 
be about 256Kbyte.


To mount it, you should obviously say that it is an RX02. If you try 
RX01, it will also be wrong for various reasons.


Data starting at byte 6657 indicates that it start right up at sector 
26. If there is nothing before, and nothing after the document, that 
makes it sound as if the data was written direct to the disk without any 
file system at all. Definitely nothing bootable in there, or else you'd 
find lots of binary junk before that text.


The zeroes and e5e5e5e5 values seems to just be filler in there.

  Johnny


On 2017-07-11 19:26, Walker Sampson wrote:

Hi everyone,

Many thanks for this feedback. A fair amount to chew on here. I’ve sent a 
request to the donor to share the disk image, if I get a positive I’ll be happy 
to throw up a Dropbox link to it for others to examine.

This may mean a problematic read of the disk itself, but addresses 0 – 
019D0 are all zeroed out, or about bytes 0 – 6655.

Data begins at byte 6657, and that is the document I mentioned. Last byte of 
the document is 73080 and then just blocks of either zero or E5E5E5E5 till the 
end of the disk.

To Paul’s point of mounting a RK05 drive – which drive should I be mounting here, 
assuming it is the RX02 disk it seems to be? “AT RX01 ” still gets 
a HALT error. Of course, as you all point out, perhaps this isn’t a bootable disk, 
period. “SH RX01” gives “RX1, 256KB, attached to test-decrx01.img, write enabled”

FYI as well, on a modern HFS+ system, the disk image file is coming in at 256 
KB.

Any thoughts on the run of zeroes and E5E5E5E5?

Thanks again,

Walker

 On 7/11/17, 6:29 AM, "Simh on behalf of Johnny Billquist" 
 wrote:

Hi.

On 2017-07-10 22:10, Walker Sampson wrote:
> Hi everyone,
>
> Let me preface this by saying that I’m unfamiliar with the original PDP
> machines. I work as a digital archivist and have received 8” floppy
> disks from which I need to recover data.
>
> I believe I have recovered at least partial data from these disks; I’ve
> connected a Y-E Data 8” floppy drive to a KryoFlux floppy disk
> controller and gotten positive sector results setting the format to a
> DEC RX02 sector image. When I investigate the resulting disk image in a
> hex editor, I am seeing clearly a report document, so I don’t believe I
> have a false positive.
>
> Outside of observing in a hex editor however, I don’t know how to access
> the disk or its contents. Using SIMH, I haven’t gotten the virtual
> machine to boot the floppy disk image.
>
> Commands “AT RK01 ” and then “BOOT RK01” give me a “HALT
> instruction, PC: 02 (HALT)” message for the PDP-11 program. The
> PDP-8 stalls indefinitely and the PDP-10 outputs “Non-existent device”
> as well.
>
> I can’t go back to the donors and ask what machines these 8” floppies
> were used with, so I’m not sure how to begin troubleshooting.
>
> Any advice in that area is much appreciated!
>
> Thanks,
>
>
> Walker

To sum things up. You can probably ignore all the questions about if
this really is some DEC floppy, what kind of format it has, and so on.
If kryoflux managed to extract data that looks valid with RX02 parameter
settings, then I'd say we can be sure it is an RX02 disk. And this
format was unique to DEC, so it can't be anything else.

Which also means, you already have managed to exact all the bits, and
most probably correct. The next question is just about restoring the
data in a more coherent form, which means getting it in the form of
files, and understanding the format of the files.

For this, we need to know what system the floppy was written on. Paul
Koning gave the most useful advice. The first few blocks will usually be
enough to find out what system the floppy was written on.

RX02 floppies could certainly be bootable, but most are not. OS/8 (and
derivatives) for the PDP-8, and RT-11 for the PDP-11 were the ones that
supported RX02 as a bootable system. Other systems supported the
floppes, but only as a way of carrying bits around, so not being able to
boot from the floppy is probably to be expected.

So, if you could give us just the first few blocks, it should be
possible to tell what file system it has, and that gives us OS, file
structure and probably the ability to work out the rest in quick order.

Johnny

--
Johnny Billquist  || "I'm on a bus
   ||  on a psychedelic trip
email: b...@softjar.se ||  Reading murder 

Re: [Simh] 8" Floppy disk image getting HALT error

[khandy21yo]

If you're interested in WPS8 RX50 format, I have a program to READ rX50 images 
and convert the files to Wordperfect format.  
Http://github.com/khandy21yo/emutools.git.  There's other stuff in there, but 
one of the subdirectories contains the source.
It's been some time since I wrote it, so I don't really remember the details.


Sent from my Galaxy Tab® A
 Original message From: Timothe Litt  Date: 
7/11/17  1:09 PM  (GMT-07:00) To: simh@trailing-edge.com Subject: Re: [Simh] 8" 
Floppy disk image getting HALT error 

VMS mount /over=id /foreign is the quickest way to identify
  files-11 and RT disks.  FILES-11 can be read directly; use
  EXCHANGE for RT-11.  Once you have the disk mounted on VMS, you
  can network it to wherever you like.
If you insist on doing things the hard way, there is low-level
  detail to worry about.


The first  track on DEC 8" floppies is reserved for boot (but not
  used) in the standard RX01/2 formats.  It's not used by any DEC
  OS.  Not even for booting (the DEC boot block is the first LBN
  following the reserved track.)


Both are 77 tracks, 1 sided, 26 sectors/track.  The rx01 is 128
  bytes/sector; the rx02 256.  So an RX01 image will be about 251KB,
  an RX02 about 501KB.


Logical blocks are 512 bytes; meaning that an LBN consists of 4
  or 2 physical sectors.  The physical sectors are interleaved.  If
  you have a physical dump of the disk (and your tools haven't
  outsmarted you), the easiest thing to do is to de-interleave it.
Use the attached utility, which documents the format & will
  interleave/deinterleave a floppy image using the usual interleave
  rules.


19D0(16) is close to 26 * 256 (short by 48 bytes), so I'd guess
  you have an rx02 and are seeing the empty boot track.  (Although
  not guaranteed, the track was usually written with all zeroes).


The 48 bytes may be left over from formatting, or an artifact of
  how you're reading the medium.  Or an indication that your
  recovery dropped something.  Hopefully it checks the CRCs..


The E5 is probably left over from formatting.  I think it was
  part of the sync pattern, and that the formatter wrote 


If you see 8-bit data, it's probably RT11 or Files-11.  These are
  self-identifying - block 1 (the second block) will have a
  filesystem name in starting at byte 760(8).  Will be DECFILE11A
  for ODS1 or DECFILE11B for ODS2, DECRT11A for RT11.  RSTS is also
  possible - I don't remember it's code, probably DECRSTS11A.  Given
  that, data (deinterleaved), humans can easily tell what you have.


RT11 files are contiguous, so recovery is easy.  FILES-11 files
  can be, but probably aren't.  You have to read mapping pointers. 
  There are tools that will do that (one of these daze I do intend
  to release mine.)
But it's much easier to just run EXCHANGE and say "COPY" by filename
:-)



As for WPS-8  - yes, it's packed into 12 bits - but it's also
encoded (I vaguely remember it as a 6-bit code with shift &
formatting - but I'd have to look up the code I wrote to translate
it.)  In any case, it would not look like text to a "modern"
filesystem.

Have fun.



On 11-Jul-17 13:26, Walker Sampson
  wrote:



  Hi everyone,

Many thanks for this feedback. A fair amount to chew on here. I’ve sent a 
request to the donor to share the disk image, if I get a positive I’ll be happy 
to throw up a Dropbox link to it for others to examine.

This may mean a problematic read of the disk itself, but addresses 0 – 
019D0 are all zeroed out, or about bytes 0 – 6655. 

Data begins at byte 6657, and that is the document I mentioned. Last byte of 
the document is 73080 and then just blocks of either zero or E5E5E5E5 till the 
end of the disk. 

To Paul’s point of mounting a RK05 drive – which drive should I be mounting 
here, assuming it is the RX02 disk it seems to be? “AT RX01 ” still 
gets a HALT error. Of course, as you all point out, perhaps this isn’t a 
bootable disk, period. “SH RX01” gives “RX1, 256KB, attached to 
test-decrx01.img, write enabled”

FYI as well, on a modern HFS+ system, the disk image file is coming in at 256 
KB.

Any thoughts on the run of zeroes and E5E5E5E5? 

Thanks again,

Walker

 On 7/11/17, 6:29 AM, "Simh on behalf of Johnny Billquist" 
 wrote:

Hi.

On 2017-07-10 22:10, Walker Sampson wrote:
> Hi everyone,
> 
> Let me preface this by saying that I’m unfamiliar with the original PDP 
> machines. I work as a digital archivist and have received 8” floppy 
> disks from which I need to recover data.
> 
> I believe I have recovered at least partial data from these disks; I’ve 
> connected a Y-E Data 8” floppy drive to 

Re: [Simh] 8" Floppy disk image getting HALT error

[Leo Broukhis]

I think that the proper image size should be 256256, as 6656 is exactly
256x26, w which is a multiple of 13, as well as 256256.

On floppy disks with 77 tracks of 26 128-byte sectors each, or 13 256-byte
sectors, track 0 could be treated as the last one when the media was
accessed at the application level (probably because it tended to be less
reliable due to the heads spending more time there).

Moreover, as the media size is not a multiple of 512, reading the last one
or two sectors may be problematic in some systems if the system block size
is 512. This hindered my recovering of the Terak boot disk for several
years.


Leo


On Jul 11, 2017 10:26 AM, "Walker Sampson" 
wrote:

Hi everyone,

Many thanks for this feedback. A fair amount to chew on here. I’ve sent a
request to the donor to share the disk image, if I get a positive I’ll be
happy to throw up a Dropbox link to it for others to examine.

This may mean a problematic read of the disk itself, but addresses 0 –
019D0 are all zeroed out, or about bytes 0 – 6655.

Data begins at byte 6657, and that is the document I mentioned. Last byte
of the document is 73080 and then just blocks of either zero or E5E5E5E5
till the end of the disk.

To Paul’s point of mounting a RK05 drive – which drive should I be mounting
here, assuming it is the RX02 disk it seems to be? “AT RX01 ”
still gets a HALT error. Of course, as you all point out, perhaps this
isn’t a bootable disk, period. “SH RX01” gives “RX1, 256KB, attached to
test-decrx01.img, write enabled”

FYI as well, on a modern HFS+ system, the disk image file is coming in at
256 KB.

Any thoughts on the run of zeroes and E5E5E5E5?

Thanks again,

Walker

 On 7/11/17, 6:29 AM, "Simh on behalf of Johnny Billquist" <
simh-boun...@trailing-edge.com on behalf of b...@softjar.se> wrote:

Hi.

On 2017-07-10 22:10, Walker Sampson wrote:
> Hi everyone,
>
> Let me preface this by saying that I’m unfamiliar with the original
PDP
> machines. I work as a digital archivist and have received 8” floppy
> disks from which I need to recover data.
>
> I believe I have recovered at least partial data from these disks;
I’ve
> connected a Y-E Data 8” floppy drive to a KryoFlux floppy disk
> controller and gotten positive sector results setting the format to a
> DEC RX02 sector image. When I investigate the resulting disk image in
a
> hex editor, I am seeing clearly a report document, so I don’t believe
I
> have a false positive.
>
> Outside of observing in a hex editor however, I don’t know how to
access
> the disk or its contents. Using SIMH, I haven’t gotten the virtual
> machine to boot the floppy disk image.
>
> Commands “AT RK01 ” and then “BOOT RK01” give me a “HALT
> instruction, PC: 02 (HALT)” message for the PDP-11 program. The
> PDP-8 stalls indefinitely and the PDP-10 outputs “Non-existent device”
> as well.
>
> I can’t go back to the donors and ask what machines these 8” floppies
> were used with, so I’m not sure how to begin troubleshooting.
>
> Any advice in that area is much appreciated!
>
> Thanks,
>
>
> Walker

To sum things up. You can probably ignore all the questions about if
this really is some DEC floppy, what kind of format it has, and so on.
If kryoflux managed to extract data that looks valid with RX02 parameter
settings, then I'd say we can be sure it is an RX02 disk. And this
format was unique to DEC, so it can't be anything else.

Which also means, you already have managed to exact all the bits, and
most probably correct. The next question is just about restoring the
data in a more coherent form, which means getting it in the form of
files, and understanding the format of the files.

For this, we need to know what system the floppy was written on. Paul
Koning gave the most useful advice. The first few blocks will usually be
enough to find out what system the floppy was written on.

RX02 floppies could certainly be bootable, but most are not. OS/8 (and
derivatives) for the PDP-8, and RT-11 for the PDP-11 were the ones that
supported RX02 as a bootable system. Other systems supported the
floppes, but only as a way of carrying bits around, so not being able to
boot from the floppy is probably to be expected.

So, if you could give us just the first few blocks, it should be
possible to tell what file system it has, and that gives us OS, file
structure and probably the ability to work out the rest in quick order.

Johnny

--
Johnny Billquist  || "I'm on a bus
   ||  on a psychedelic trip
email: b...@softjar.se ||  Reading murder books
pdp is alive! ||  tryin' to stay hip" - B. Idol
___
Simh mailing list
   

Re: [Simh] 8" Floppy disk image getting HALT error

[Walker Sampson]

Hi everyone,

Many thanks for this feedback. A fair amount to chew on here. I’ve sent a 
request to the donor to share the disk image, if I get a positive I’ll be happy 
to throw up a Dropbox link to it for others to examine.

This may mean a problematic read of the disk itself, but addresses 0 – 
019D0 are all zeroed out, or about bytes 0 – 6655. 

Data begins at byte 6657, and that is the document I mentioned. Last byte of 
the document is 73080 and then just blocks of either zero or E5E5E5E5 till the 
end of the disk. 

To Paul’s point of mounting a RK05 drive – which drive should I be mounting 
here, assuming it is the RX02 disk it seems to be? “AT RX01 ” still 
gets a HALT error. Of course, as you all point out, perhaps this isn’t a 
bootable disk, period. “SH RX01” gives “RX1, 256KB, attached to 
test-decrx01.img, write enabled”

FYI as well, on a modern HFS+ system, the disk image file is coming in at 256 
KB.

Any thoughts on the run of zeroes and E5E5E5E5? 

Thanks again,

Walker

 On 7/11/17, 6:29 AM, "Simh on behalf of Johnny Billquist" 
 wrote:

Hi.

On 2017-07-10 22:10, Walker Sampson wrote:
> Hi everyone,
> 
> Let me preface this by saying that I’m unfamiliar with the original PDP 
> machines. I work as a digital archivist and have received 8” floppy 
> disks from which I need to recover data.
> 
> I believe I have recovered at least partial data from these disks; I’ve 
> connected a Y-E Data 8” floppy drive to a KryoFlux floppy disk 
> controller and gotten positive sector results setting the format to a 
> DEC RX02 sector image. When I investigate the resulting disk image in a 
> hex editor, I am seeing clearly a report document, so I don’t believe I 
> have a false positive.
> 
> Outside of observing in a hex editor however, I don’t know how to access 
> the disk or its contents. Using SIMH, I haven’t gotten the virtual 
> machine to boot the floppy disk image.
> 
> Commands “AT RK01 ” and then “BOOT RK01” give me a “HALT 
> instruction, PC: 02 (HALT)” message for the PDP-11 program. The 
> PDP-8 stalls indefinitely and the PDP-10 outputs “Non-existent device” 
> as well.
> 
> I can’t go back to the donors and ask what machines these 8” floppies 
> were used with, so I’m not sure how to begin troubleshooting.
> 
> Any advice in that area is much appreciated!
> 
> Thanks,
> 
> 
> Walker

To sum things up. You can probably ignore all the questions about if 
this really is some DEC floppy, what kind of format it has, and so on. 
If kryoflux managed to extract data that looks valid with RX02 parameter 
settings, then I'd say we can be sure it is an RX02 disk. And this 
format was unique to DEC, so it can't be anything else.

Which also means, you already have managed to exact all the bits, and 
most probably correct. The next question is just about restoring the 
data in a more coherent form, which means getting it in the form of 
files, and understanding the format of the files.

For this, we need to know what system the floppy was written on. Paul 
Koning gave the most useful advice. The first few blocks will usually be 
enough to find out what system the floppy was written on.

RX02 floppies could certainly be bootable, but most are not. OS/8 (and 
derivatives) for the PDP-8, and RT-11 for the PDP-11 were the ones that 
supported RX02 as a bootable system. Other systems supported the 
floppes, but only as a way of carrying bits around, so not being able to 
boot from the floppy is probably to be expected.

So, if you could give us just the first few blocks, it should be 
possible to tell what file system it has, and that gives us OS, file 
structure and probably the ability to work out the rest in quick order.

Johnny

-- 
Johnny Billquist  || "I'm on a bus
   ||  on a psychedelic trip
email: b...@softjar.se ||  Reading murder books
pdp is alive! ||  tryin' to stay hip" - B. Idol
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