labuda@endot.UUCP (Dave Labuda) (01/06/85)
Subject: OS info request Newsgroups: net.architecture I am preparing a paper on the wonders of the UNIX operating system, and one of (in my opinion) its strongest points is its very small, clean system call interface. I would like to contrast this to some huge and ugly interfaces, but I am not familiar with other OS's. I would therefore appreciate it if anyone out there who knows VMS or some other large scale OS could let me know how many system calls the OS supports, and about how large the source code for the OS is (give or take a few thousand lines). Please mail me personally so as not to clutter the net, and if I get enough queries I will post any results. Thank you. David Labuda Endot Inc decvax!cwruecmp!labuda
tli@uscvax.UUCP (Tony Li) (01/11/85)
> Subject: OS info request > Newsgroups: net.architecture > > I am preparing a paper on the wonders of the UNIX operating system, and > one of (in my opinion) its strongest points is its very small, clean > system call interface. I would like to contrast this to some huge and > ugly interfaces, but I am not familiar with other OS's. I would therefore > appreciate it if anyone out there who knows VMS or some other large scale > OS could let me know how many system calls the OS supports, and about how > large the source code for the OS is (give or take a few thousand lines). > Please mail me personally so as not to clutter the net, and if I get enough > queries I will post any results. Thank you. > > David Labuda Hi Dave, I don't consider this a fair contest. How many system calls is just not a good metric of a OS's worth. Let me give you some guesstimates: OS # of system calls ------------ ----------------- CP/M 2.2 40 Unix 100 Tops-20 100 CCP/M 150 VMS 250 My point is this: OS's have different capabilities. And capabilities take system calls to implement. Would you argue that CP/M 2.2 is better than Unix because it has fewer system calls than Unix? I hope not. (PS. If so, have I got an OS for you. It's the best OS of all. You can't call it! ;-) Does the number of system calls indicate anything? I'd say that Tops-20 is definitely a more capable and complex system than VMS, and I think that even you would have to agree that VMS provides more facilities than Unix. So the number of system calls doesn't seem to indicate much of anything. If you're going to expound the virtues of Unix, concentrate on: ease of modification, large number of available tools, excellent software development environment, and portability. Stay away from: Efficiency, security, and user-friendliness. Cheers, Tony ;-) -- Tony Li ;-) Usc Computer Science Uucp: {sdcrdcf,randvax}!uscvax!tli Csnet: tli@usc-cse.csnet Arpa: tli@usc-ecl
ka@hou3c.UUCP (Kenneth Almquist) (01/15/85)
To correct a few figures posted to the net: System V has about 60 system calls, 9 of which are optional IPC calls. VMS has about 84 system services, which does not include services provided by things like the record management system. I don't have a count of system calls for TOPS-20, but I'm sure that it is more than 100. The number of system calls is not the entire story; TOPS-20 provides an overwhelming number of options on some of its system calls. Kenneth Almquist
kvc@scgvaxd.UUCP (Kevin Carosso) (01/22/85)
In article <1399@uscvax.UUCP> tli@uscvax.UUCP (Tony Li) writes: >> >> David Labuda > >Hi Dave, > >I don't consider this a fair contest. How many system calls is just not >a good metric of a OS's worth. Let me give you some guesstimates: > > OS # of system calls > ------------ ----------------- > CP/M 2.2 40 > Unix 100 > Tops-20 100 > CCP/M 150 > VMS 250 > While I agree completely with Tony's (hi Tony, how are things going?) premise that this isn't such a good thing to base an O/S comparison on (but it's an interesting thing to look at, nonetheless), I'd like to point out that he overestimated the number of system services in VMS. VMS V3 has 89 system services and 31 RMS services (filesystem interface) for a total of 120. VMS V4 has 119 system services and the same 31 RMS services, for a total of 150. /Kevin Carosso scgvaxd!engvax!kvc Hughes Aircrft Co.
jlg@lanl.ARPA (01/23/85)
> VMS V3 has 89 system services and 31 RMS services (filesystem interface) for > a total of 120. VMS V4 has 119 system services and the same 31 RMS services, > for a total of 150. Now if they could get rid of those 31 RMS 'services', VMS would be on its way to becoming a usable system. J. Giles
alan@drivax.UUCP (Alan Fargusson) (01/29/85)
MPE on the HP3000 has no system calls.
System services are implemented in priveleged segments, and are
called in the same way as any user subroutine. A segment is priveleged
(can execute protected instructions) if it is compiled with 'option preveleged'
and the owner of the file that it resides in has preveleged permission.
How would you rate this system?
--
Alan Fargusson.
{ ihnp4, sftig, amdahl, ucscc, ucbvax!unisoft }!drivax!alanguy@rlgvax.UUCP (Guy Harris) (01/31/85)
> MPE on the HP3000 has no system calls. > > System services are implemented in priveleged segments, and are > called in the same way as any user subroutine. A segment is priveleged > (can execute protected instructions) if it is compiled with 'option preveleged' > and the owner of the file that it resides in has preveleged permission. > > How would you rate this system? By classifying all subroutines residing in privileged segments which are intended to be called from non-privileged segments as system calls. MULTICS worked the same way, although most "system calls" were NOT able to execute privileged instructions; they merely ran in ring 0 (or 1) which gave them access to more system data structures and access to the very few routines which could actually execute privileged instructions. Then again, somebody discussed RMS calls in VMS under the same heading. In VMS, RMS happens to run in "executive" mode, but under RSX-11 it runs in user mode as a regular library. So are RMS calls system calls or not? I think rating systems by the number of system calls is as useful as rating processors by the size of their instruction set; i.e., not useful at all. Rate them by what you can do using that system, and how efficiently and conveniently you can do it. Guy Harris {seismo,ihnp4,allegra}!rlgvax!guy
tli@uscvax.UUCP (Tony Li) (01/31/85)
> > VMS V3 has 89 system services and 31 RMS services (filesystem > > interface) for > > a total of 120. VMS V4 has 119 system services and the same 31 RMS > > services, > > for a total of 150. > > > Now if they could get rid of those 31 RMS 'services', VMS would be on its > way to becoming a usable system. > > J. Giles Those 31 RMS services are more useful than any version of a file system than I've ever heard of on a Unix system. ;-) -- Tony Li ;-) Usc Computer Science Uucp: {sdcrdcf,randvax}!uscvax!tli Csnet: tli@usc-cse.csnet Arpa: tli@usc-ecl