robin@medstar.UUCP (Robin Cutshaw) (07/15/85)
As usual, this posting relates to IBM Xenix 1.0 for the PC/AT... There is a problem with the shared data code with Xenix. It seems that a program compiled with the large model cannot write into shared data space of programs compiled with the small or medium models. Large may talk to large but that's it. There is no problem with small and medium models talking to each other and they can write into large model space but just not vica-versa. (IBM is working on it). On the previous posting reguarding the "Panic Kernel (easy to do)", IBM has really shown their colors. The jist of the article was that if you call getcwd() between sdenter() and sdleave() you will get a kernel panic (if you have stdio.h included and a few other things). IBM's official response to this is "SEE PAGE 2-194 of the Software Command Reference where it says 'system calls should be avoided between sdenter and sdleave calls'". This is their only response! So now everyone who doesn't read and follow the directions on page 2-194 will be able to easily panic and crash the Xenix kernel. UNBEWEVIBLE! If you look at the reference page for nlist() you will see a reference to xlist(). This is the equivalent for x.out type with a little different format. You will find no reference page to xlist() and IBM says that their will be none and in fact the reference on nlist to xlist will be removed. Even so, if you look at /usr/include/a.out.h you will see the format for xlist() use and it works well. Reguarding CPP, the command reference notes that this is called as the first pass of cc. This is not the case. CPP is almost unusable due to the fact that it is not compatible with the c pre-processor used by cc (for example, their is no way to specify identifier names larger than 8 chars). 'till I crash again... -robin -- ---- Robin Cutshaw uucp: ...!{akgua,gatech}!medstar!robin
phil@amdcad.UUCP (Phil Ngai) (07/18/85)
In article <183@medstar.UUCP> robin@medstar.UUCP (Robin Cutshaw) writes: > >As usual, this posting relates to IBM Xenix 1.0 for the PC/AT... > >On the previous posting reguarding the "Panic Kernel (easy to do)", IBM has >really shown their colors. The jist of the article was that if you call >getcwd() between sdenter() and sdleave() you will get a kernel panic (if you >have stdio.h included and a few other things). IBM's official response to >this is "SEE PAGE 2-194 of the Software Command Reference where it says 'system >calls should be avoided between sdenter and sdleave calls'". This is their >only response! So now everyone who doesn't read and follow the directions on >page 2-194 will be able to easily panic and crash the Xenix kernel. Why are you using sdenter if you haven't read the man page for it? Or is reading two whole pages of documentation too much effort? --
robin@medstar.UUCP (Robin Cutshaw) (07/19/85)
> Why are you using sdenter if you haven't read the man page for it? > Or is reading two whole pages of documentation too much effort? > -- As usual, someone has to put in their cent-and-a-half. The point wasn't that it was a big deal to read the man pages for shared data, but that any user can at will crash the system which is not necessarily the effect of choice, and IBM just says read the manual. I probably shouldn't have even taken the time to respond... -robin -- ---- Robin Cutshaw uucp: ...!{akgua,gatech}!medstar!robin