SAGE@LL.ARPA (04/13/88)
The maximum user area displayed by SHOW.COM is not the highest one you can log into but the highest one you are allowed to reference. SHOW does display on one of its screens whether or not the Z33 command processor will log into high user numbers. Z33 (and Z34) is the only command processor that optionally allows user numbers above 15 to be logged into, and there is considerable risk in doing so. I implemented that feature as an intellectual challenge for experimenters who do not mind living on the edge. I do not recommend logging into high user areas as a matter of course. The fact that CD33 will not log into them is a reflection of the sanity normally built into that program. It is smart enough to check DU and DIR references for a valid login range. It was an oversight that it does not check the HIGHUSER option bit in the Z33 command processor to see if the high user numbers are allowed. I will try to get someone to make the required change (not at all difficult, since there is a Z33LIB library routine for checking the HIGHUSER flag bit, I believe). With Z34 and the extended environment, there is a full drive vector to replace the overly simplistic maxdrive byte. CD should be upgraded to observe the limits imposed by that vector in addition to the maxdrive limit. In this way, CD can, like the Z34 command processor, respect holes in the drive map.
mlinar@eve.usc.edu (Mitch Mlinar) (04/15/88)
In article <SAGE.10354880@LL.ARPA> SAGE@LL.ARPA writes: > > The maximum user area displayed by SHOW.COM is not the highest one you >can log into but the highest one you are allowed to reference. SHOW does >display on one of its screens whether or not the Z33 command processor will >log into high user numbers. Z33 (and Z34) is the only command processor >that optionally allows user numbers above 15 to be logged into, and there is Wrong, Jay. QP/M (which you may not know about, although it has been around since 1983) has always offered 31 user areas. In fact, *all* of the programs associated with it (QSTAT, QPIP, CD, DIR, MAKE, etc.) know about 32 user areas. >considerable risk in doing so. I implemented that feature as an >intellectual challenge for experimenters who do not mind living on the edge. >I do not recommend logging into high user areas as a matter of course. > Here, I agree with Jay. I have found it *very* rare that anyone needs that many user areas. Clearly, you never would want it on a floppy (not enough storage to make it worthwhile). Furthermore, CP/M+ trashes files above user number 15 (it only looks at users 0 to 15 to make the allocation bit map) if given half a chance. On a hard drive, if you seem to be exceeding the limit, you should look at your hard drive setup. You might consider breaking your hard drive up into smaller logical drives which should give some breathing room. Although QP/M has always supported 31 user areas, most of the public programs which support du: have problems above user 15 (especially if they want to be compatible with CP/M+). I agree with Jay that it should be used with some care. -Mitch