[Info-vax] Anyone interested in another public access system

[Richard B. Gilbert]

Bill Gunshannon wrote:
> In article <KbednRfOOfbZKn3UnZ2dnUVZ_g6dnZ2d at giganews.com>,
> 	"Richard B. Gilbert" <rgilbert88 at comcast.net> writes:
>> Bill Gunshannon wrote:
>>> In article <49DF8CAD.5618BE77 at spam.comcast.net>,
>>> 	David J Dachtera <djesys.no at spam.comcast.net> writes:
>>>> Bill Gunshannon wrote:
>>>>> In article <49DD4688.6EF7C2 at spam.comcast.net>,
>>>>>         David J Dachtera <djesys.no at spam.comcast.net> writes:
>>>>>> Michael Kraemer wrote:
>>>>>>> Bob Koehler schrieb:
>>>>>>>
>>>>>>>>    UNIX is still a two-mode system which forks new processes every time
>>>>>>>>    it turns around, and has no concept of files beyond stream of bytes.
>>>>>>> And ? So what. Essentially it *is* a sack of bytes.
>>>>>>> Records grouped in blocks (as in MVS and VMS) are relics
>>>>>>> from the era of slow tape and disk drives which had to be accessed
>>>>>>> at a rather low level.
>>>>>> Well, no, not really. Every "row" from a table that is retrieved froma
>>>>>> database constitutes a "record". Every POST operation in HTTP returns a
>>>>>> "record", complex as it may be.
>>>>>>
>>>>>> Gotta look past the trees to see the forest.
>>>>> I did look past the trees (records) and saw the whole forest.  And it is
>>>>> composed entirely of bytes. 
>>>> ...and how are those bytes organized? (Yes, Virginia, there *IS* a
>>>> structure!)
>>>>
>>>> Try again.
>>>>
>>> They are not organized.  An artificial structure is imposed at the
>>> application layer.  All computer data is composed of bytes. (well,
>>> bits if you go low enough)  Any "structure" is artificial and
>>> imposed after the fact.  There are no records in memory.  Just bytes.
>>> So then, why should one assume there is anything different anywhere
>>> else?  There are no records built into my disks.  A disk from one
>>> computer can be used on another.  I can take the disk from my VMS
>>> machine with all those "structured file types" put it in my unix
>>> machine and it works just fine.  The disk does not store things
>>> as anything but blocks containing bytes.  Any structure is artificial
>>> and at a very high level in the process.
>>>
>>> I have never tried it, but I would imagine it is perfectly doable to
>>> take a VMS disk, hook it up to a unix box and read the data from it.
>>>
>>> bill
>>>
>> Of course you could read the data from it!  But Unix would probably not 
>> understand what space was in use and what was free.  You could find and 
>> read files only with great difficulty.  You would have to port a big 
>> chunk of RMS to read files and make sense of them.
>>
>> There is a huge difference between reading raw data from a disk, which 
>> any O/S can do, and reading files.
> 
> I didn't mean reding the raw bits.  I meant interpreting the data.  All of
> which could be done at the application level.  Given a description of the
> format of the data, there is nothing to prevent reading bytes and extracting
> usable data.
> 
> bill
>  
> 

You can read raw disk blocks and maybe understand what you find in them. 
  That's not the same as being able to get directory listings or open 
and read a file.

I'm sure that, with a great deal of effort, a Unix program that could 
find its way around an ODS-2 file system could be written.  I can't see 
why anyone would want to; the effort required would be enormous and the 
rewards meager!