shapiro@wdl1.UUCP (David Shapiro) (04/11/88)
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I have been working with PC/Ingres recently and I thought I
would share a few comments.
I have it running on a PS/2 50. We originally bought it to port
our applications from our Unix VAX to the pc. RTI told us that
we wouldn't have many problems and many people have done this
before. Well, there were still many surprises. I'll list what
I consider pluses and minuses of the product.
-- You cannot use any of the embedded languages with OSL. That
is, the procedures in ABF are strictly OSL procedures (not
mixed OSL or EQUEL/C (ESQL/C) as in the mainframe product).
This is a serious limitation to us, since we have specialized
routines we like to use with our applications. RTI just says
recode it in OSL. But we loose things such as the direct scroll,
optimizing some queries, and table field editors we use. It
turns out that ABF does not compile OSL down to equel/c, and
finally to c, which is cc'ed. ABF builds a runnable object code
directly from OSL, which explains why we can't link embedded
languages with OSL. To get around the whole problem, I'll
compile everything to equel/c on the mainframe, download to the
pc, and use the equel/c compiler (with Microsoft/c) to run the
application.
-- Due to memory limitations on the pc, you can have no more
than 100 frames in an application, and no more than 4 frames
active at one time (4 frames on the stack). I have gotten away
with up to 6 frames but had problems with other frames.
-- Also due to pc memory, frame size is limitied. However you
can set a frame size variable to allow for larger frames. This
is at the cost of space for the ingres backend and query
processor.
-- Does not support isam disk structures.
-- No 'repeat' in the embedded language.
++ Nice to have your choice of editors in ABF.
++ If you have a color monitor, the color attributes make the
frames very attractive, though there is a bug so that some of
the colors are not correct with their attribute numbers.
++ Response with the frames is very nice. Response time is of
course not dependent on a time slice, which makes table field
scrolls very fast.
++ Documentation is well done, but not nearly as inclusive as
the mainframe documentation.
There are a couple of other interesting products to note.
PC/Link should allow your pc to access a database stored on the
mainframe. And if your pc's are networked, this is supposed to
be a network friendly product. We haven't tried either of
these.
All in all, it seems to perform like its mainframe cousin. I
haven't done any speed or disk size tests yet, but I downloaded
a couple of 12,000 row tables and it handled them and joins
between them with no problems. For more information on porting
to the pc, see technical note 077.all on the latest ingres
release tapes. I would recommend pc/ingres to mainframe ingres users
who have a need to run their applications on the pc or who
would like to do development on portions of an application and
upload to the mainframe for integration. I wouldn't recommend
this to first time database users since there are other
products that are better tuned to the pc than pc/ingres (better
use of color and better use of memory).
Has anyone else had experience with the product? Please email
your comments, suggestions, bug work-arounds. Thank you,
David Shapiro Ford Aerospace Corp.
Western Development Laboratories
shapiro@ford-wdl1.arpa
...{sgi,sun,ucbvax}!wdl1!shapiro
All opinions stated here are my own, not my employer's.