Two disclaimers: One, these are my opinions only; two, I'm not running the absolute latest release of the software I'm discussing.
The major problem I have found with ACIS 4.3 is the lack of a production-quality C compiler. ACIS comes with two C compilers, "High C" from MetaWare, Inc. (hc), and a version of the Portable C Compiler (pcc). AOS apparently comes with three compilers, pcc and two versions of hc.
hc claims to be draft ANSI conformant, but really doesn't come close. A large number of Makefiles invoke hc with the "-U__STDC__" switch as a matter of course and a number of system-wide header files have constructs surrounded by "#if defined(__STDC__) && !defined(__HIGHC__)".
hc has a number of bugs--the usual method of compiling a program is to run a "make", compiling what one can with hc, and then doing a "make CC=pcc" to compile the rest. Sometimes this won't work--I have one program that I simply cannot compile on the RT because it tickles bugs in both compilers. Most of the bugs I reported seem to be fixed in the latest release, but from what I read on the xperts mailing list, the latest release still has problems.
hc also has some static limits on the size of internal data structures which are (by definition) too low. APAR 407, which complains about the too-low limit on the number of nodes, has been open for over a year. It also generates the "stabs" debugging information in the wrong format--when porting the GNU debugger, the programmer had to put in a heuristic to determine which compiler was used to compile the program and deal with hc as a special case.
pcc would fit the bill of a production-quality compiler, but it still has a few bugs which IBM refuses to fix. They wish to "... [promote] the use of a C compiler in the IBM Academic Operating System 4.3 that follows the Proposed ANSI Standard for the C programming language (hc) over a C compiler that does not (pcc)...". Right. Since when does hc follow the draft ANSI standard?
If you manage to get your programs compiled, the APC RT is a nice, fast piece of metal. I haven't used the 6152's all that much, but they leave a rubber-band-and-chewing-gum taste in my mouth. The 8514 display card (am I getting the numbers right?) for the 6152 is undocumented, or at least what documentation exists is currently IBM Confidential Restricted.
IBM has this tendency to foist off monitors that are much too small. Most RT monitors around here are 3rd party.
I have not had any problems with hardware service; in fact I've been fairly impressed. I am at CMU though--there are a lot of the buggers around here, so the IBM Techs are somewhat familiar with them.
Stay away from AIX if at all possible. I spent three days installing AIX on a machine--managed to bring up the network and create a user before my boss figured that I had better things to do. The manuals have a low signal-to-noise ratio--I remember spending lots of time flipping through pages of blue-ink examples looking for the single item of information that I needed. I also remember some bogosities like having to specifiy at configuration time whether a given pty was to have a getty running on the slave end.
-- _.John G. Myers Internet: John....@cs.cmu.edu LoseNet: ...!seismo!ihnp4!wiscvm.wisc.edu!give!up "Whenever faced with a problem, some people say `Lets use AWK.' Now, they have two problems." -- D. Tilbrook --