Re: CRC in Ada?

[ohk@edeber.tfdt-o.nta.no (Ole-Hjalmar Kristensen FOU.TD/DELAB)]

In article <E6Lpv3.AoL@world.std.com> bobduff@world.std.com (Robert A Duff) writes:

<stuff deleted>

   I still don't think it's a "mistake" to expect buffering to be done by
   standard packages, rather than by every user's program.  I mean, you
   have to tell the thing that you're planning to read sequentially through
   the file, but beyond that, the application program shouldn't have to
   worry about it.

   (When I programmed on VAX/VMS, I was appalled at the complexity of the
   Record Management Services.  I still don't know why all that complexity
   is necessary, as compared to the Unix notion that a file is a sequence
   of bytes.  But I could be wrong -- I write compilers, mostly, which
   don't need "fancy" I/O facilities.)

Nor do data base management systems. If you use something like the
RMS, your DBMS is probably not going to be very portable, and it is
not very likeley that the RMS idea of what properties and physical
layout a record should have matches the DBMS's ideas. I could make
similar complaints about the crazy idea of building so-called
"reliable" network protocols without regard to the rest of the system
(like TCP/IP), but I'll stop here.

The basic problem is that designers of services like file systems and
network protocols must assume soemthing about their clients. Often
that assumption is wrong, in which case the value of the service is
rather dubious. It is NOT easy to build complex mechanisms which must
be useable in a variety of contexts.

   Note that Ada compilers don't typically use Text_IO to read the source
   code!  ;-)

   - Bob