topic Re: Check sum in Operating System - OpenVMS

Check sum

Wim Van den Wyngaert — Mon, 26 Mar 2007 02:04:07 GMT

I use a checksum/ima to checksum my exe files.

After the time change in Belgium this weekend, I got a new checksum for sys$common:[sysldr]sys$base_image.exe. And this on 4 nodes.

The file is not modified (dir/fu) since 2002.

Why ???

Wim

Re: Check sum

Ian Miller. — Mon, 26 Mar 2007 05:38:55 GMT

the datetime is stored in the base image.
Do a SET TIME=xxx command and you will see that file gets updated.

Re: Check sum

Wim Van den Wyngaert — Mon, 26 Mar 2007 05:39:59 GMT

Ian,

I suspected something like that. Is it normal that the moddat is not modified ?

Wim

Re: Check sum

Hein van den Heuvel — Mon, 26 Mar 2007 06:45:56 GMT

That write goes behind the back of the file system. At boot time the LBN number for the block with the system time is remembered. During SET TIME, after a revalidation of the BOOT_CBLOCK a channel is assigned and a QIO WRITELBLK is issued. No 'file' is opened. So no modification date change.

fwiw,
Hein.