skennedy@ihlpb.ATT.COM (S. Kennedy) (02/21/89)
Informix SQL just happily trashed my OS. weeeeee.
What happened? I haven't the foggiest idea, but trash it did.
SCENARIO:
---------
Informix SQL 2.10.0b on SCO SYSV 2.2.2, NEC 386 w/4M of Ram and 66M hard drive.
2 users most of the time. Using clustered indexes. Everything working fine when
*WHAM*
Nothing seems to work. Fine. I get a call telling me something's up.
Tromp over on a Friday nite to take a look. Tells me that the I got a C-ISAM
error when trying to read from the table. Great.
So I run bcheck. Tells me I have a missing magic number. Look up in the
manual and cannot find what a "magic number" is so I can repair. Perfect.
I start poking around looking a some more of the system. I find:
.per files turned into device drivers.
.frm files turned into directories containing an exact copy of my .dbs
directory (hosed version).
most of /usr/bin hosed.
*all* user account files have been replaced with copies of the terminfo
of a visual terminal.
I have no choice but to back to Thursday's tape to find that it, also is
shot to hell. Went back to Wednesday's tape which (luckily :-( ) was still
sane. Spend 10 hours reinstalling and everything's back up.
So tell me, what happened??
What is a "magic number" and how can it be fixed when MIA?
On a side note, in Informix 4GL, why is the word "dirty" a reserved word,
but never described anywhere in the manuals as to it's use? A foreshadowing
of something to come??
I really like Informix, but if this happens again, I'm not liable for
my actions ...... :-)
Shawn Kennedy skennedy@ihlpb.att.com
AT&T Bell Labs att!ihlpb!skennedy
Disclaimer: This has nothing to do with AT&T, BL or any connected facility.bgolden@infmx.UUCP (Bernard Golden) (02/21/89)
In article <9662@ihlpb.ATT.COM> skennedy@ihlpb.UUCP (S. Kennedy) writes: > >Informix SQL just happily trashed my OS. weeeeee. > >What happened? I haven't the foggiest idea, but trash it did. > > > >On a side note, in Informix 4GL, why is the word "dirty" a reserved word, >but never described anywhere in the manuals as to it's use? A foreshadowing >of something to come?? Dirty is a word used as part of a read mode in our Turbo database engine (i.e., "dirty read"); therefore it can't be used in other parts of our products. I'm sorry about your problem -- did you contact our tech support folks? -b line feed stuff
baker@hpfcmr.HP.COM (Jim Baker) (02/23/89)
> What is a "magic number" and how can it be fixed when MIA?
A magic number is a bit pattern placed in a specific location to authenticate
the data structures/objects. For instance, a.out executables contain a magic
number to define the type of executable: demand paged MC68020.
See the man page file(1).
The data structure that defines the format of the BSD filesystem
(super-block) contains a magic number to assure that some random
bits on the disk aren't masquerading as the super-block and in your
case to trap instances of super-block corruption. The BSD super-block is
replicated in several locations on the disk so that in the event the
primary super-block gets trashed, another structure can be used to
recover the filesystem. The block offset of the spare super-blocks
can be given at file system check time to salvage (if possible) the
file system. Spare block locations are listed when the file system is
built and should be recorded & saved (newfs).
Good luck,
Jim Baker
Hewlett-Packard