VMS vs. UNIX file system

[Chris Torek]

In article <3438 at crash.cts.com> jeh at crash.cts.com (Jamie Hanrahan) writes:
>... the Unix byte stream uses perfectly legitimate data as a record
>separator.

Do you know what a `byte stream' is?  Byte streams do not have records;
they can hardly have record separators.  If you want records in a Unix
file system file, you must define them yourself.  This is what Barry
Shein was talking about.

>Barry goes on to say that you should be able to open any file as a byte
>stream and not get an error.  Well, you can do the equivalent under VMS--
>you can open any file, sequential, relative, or indexed, for sequential
>access, and RMS will happily hand you the records in order (in order by
>primary key if it's an indexed file).  And if you prefer a byte-stream
>... you or the system can provide a set of byte-stream interface routines
>to do that with a record-oriented file system.

Simulating a byte stream on top of records is considerably more
difficult than simulating records on top of a byte stream.  I have been
lead to believe that, under VMS, each different kind of record-oriented
file must be read with a different primitive.  (You must also provide a
buffer that is as large as the largest record.)  Hence to simulate a
byte stream, you must know about every possible record format.

On the other hand, to simulate a record format, you must know about
every possible byte stream.  Fortunately, there is only one possible
byte stream, by the definition of `byte stream'. . . .
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris at mimsy.umd.edu	Path:	uunet!mimsy!chris