Re: Comments on the website from people on twitter...

[Dr Slivnik Tomaž MA (Cantab) MMath (Cantab) PhD (Cantab) FTICA]

> I have a feeling I know which bug you're talking about.  There was a PPC bug 
> which allowed a very short program to freeze the system due to a processor 
> bug which caused the CPU to enter supervisor mode, but I could be mistaken.   
> This bug as I recall was not something that could be trapped or prevented by 
> the operating system.   There was a similar issue on intel processors a long 
> time ago caused by a faulty FDIV instruction which could be exploited easily 
> and used to freeze the computer.  I tried it once on my old Pentium when I 
> used to run OPENSTEP on it… it worked just fine.  So I'm not sure that these 
> crashes you're referring to are actually issues which are related to a OS 
> level issue.

No.

#include <fcntl.h>
main () { struct log2phys x; fcntl (open ("/",O_RDONLY), F_LOG2PHYS, &x); }
-----------------
hdiutil create -size 2.5G testfile.dmg

Then:

#include <stdlib.h>
#include <fcntl.h>

main () { int fds; struct radvisory ra; if ((fds = open 
("testfile.dmg",O_RDONLY,0)) < 0) exit (1); ra.ra_offset = 0; ra.ra_count  = 
0x7ffff001; fcntl (fds,F_RDADVISE,&ra); }
---------------------------------
Either of those two code snippets will kernel panic Mac OS X.4 when run on an 
HFS+ filesystem. These are two of the simpler examples I found. I found 
countless other examples which I used to report to Apple when they still had 
some technically competent people working for them and actually understood bug 
reports and fixed bugs. I stopped reporting bugs to Apple after they dismissed 
out of hand as "Works as intended" too many of my carefully prepared bug 
reports (which take time and effort to prepare) of what were very clearly 
serious bugs.

> I use Mail.app every single day to handle my 200,000+ message mailbox.   It 
> does so beautifully.

My experience with Mail.app on OS X has been different. It has lost a lot of my 
mail messages. On one occasion, it lost a mail message while I was in the 
process of reading it. I was looking at the message, inadvertently clicked on a 
Mailbox name in the mailbox list which switched my view to a different message. 
I tried to get back to the message I was reading, and it was gone. Completely 
gone. I was only able to recover it by scanning the raw disk image (my backups 
were in a different location and inaccessible at the time) - there was no file 
in the filesystem containing the mail message. This was the only time I caught 
Mail.app in the process of losing my message, but there have been many other 
occasions when messages that used to be there, one day would just be gone.

A couple of times Mail changed its internal format of mailboxes; a number of my 
mail messages did not survive the (automatic, invisible, unannounced) 
conversion process. I don't know where they went.

HTML message editing (on X.6 admittedly) is completely broken and unusable. 
Text pasted below certain text ends up being pasted above it, only parts of it 
get pasted, etc. etc. I am now reminded that Address Book Notes field editing 
often behaves the same. In fact, I reported these bugs to Apple, who classified 
it as a "Duplicate" bug report (thus implicitly acknowledging it).

> if you haven't used OS X since 10.4

I use 10.6. I know what 10.7 and 10.8 are like and I will never upgrade. I 
think they are a load of rubbish. I tolerate Mac OS X because it has been the 
most compatible current O.S. to NeXTstep, but in my view in each release it 
just keeps retrogressing from NeXTstep. My next laptop will run Linux or *BSD. 
YMMV.