On Thu, Sep 17, 2009 at 10:55 PM, Kris Buelens kris.buel...@gmail.com wrote:
Using V-disks: less I/O involved: no CP format, and CMS format doesn't need
to write nK data blocks all over the disk. But, V-disk pages are considered
as shared storage by CP. So, V-disk pages may stay longer in
-
From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On
Behalf Of Schuh, Richard
Sent: Thursday, September 17, 2009 4:08 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
The simplest mode of recovering data from a T-disk in CMS requires only
On Thu, Sep 17, 2009 at 10:18 PM, Gentry, Stephen
stephen.gen...@lafayettelife.com wrote:
Just did a quick test on a test VM system. CLEAR_TDisk is enabled. With
a T-DISK size of 1300 cylinders, clearing/formatting it isn't noticed,
speed wise. Would have thought I would have gotten a
: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf
Of Rob van der Heij
Sent: Friday, September 18, 2009 8:49 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
On Thu, Sep 17, 2009 at 10:18 PM, Gentry, Stephen
stephen.gen...@lafayettelife.com wrote
.
Regards,
Richard Schuh
-Original Message-
From: The IBM z/VM Operating System
[mailto:ib...@listserv.uark.edu] On Behalf Of Alan Altmark
Sent: Wednesday, September 16, 2009 6:51 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
On Wednesday, 09/16
] TDISK and SYSTEM CONFIG question.
If you have the page space to support it, you can get by without TDSK space by
using V-disk. It is always cleared very quickly, by CP, before it is used and
does not pose the security problems that you find in T-disk. A large V-disk is
also faster to format
[mailto:ib...@listserv.uark.edu] On Behalf
Of O'Brien, Dennis L
Sent: Thursday, September 17, 2009 2:15 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
What security problems in T-Disk? If you enable Clear_TDisk, there's no
security problem. Even if the system
: Thursday, September 17, 2009 11:29 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
I guess I should have read Richard's response closer. So,
I'll echo Dennis's question as well.
What security problem?
We do not have CLEAR_TDisk enabled. Every time we define a
t
Without CLEAR_Tdisk enabled, whatever data the last user stored in
T-DISK space is still present when it is allocated to the next user. To
successfully use the space with CMS you will most likely have to format
it, unless the boundaries of your TDISK allocation exactly overlay the
previous
As mentioned in my question below, we have to format the defined temp
minidisk every time. So, from that point of view, the data is gone. I
didn't think of the DDR situation. However, a class G user would have to
know where the T-DISK area is defined. They cannot issue a QUERY ALLOC
TDISK
-Original Message-
From: The IBM z/VM Operating System
[mailto:ib...@listserv.uark.edu] On Behalf Of Tom Rae
Sent: Thursday, September 17, 2009 12:05 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: TDISK and SYSTEM CONFIG question.
Without CLEAR_Tdisk enabled, whatever data the last user
As far as I know, without Clear_Tdisk, CP still formats the first cylinder
of a T-disk, so ACCESS will always fail even if you'd get a T-disk at the
same place as the previous user. But, with DDR or alike one could still
find raw data on other cylinders.
With Clear-Tdisk enabled, CP will format
would have to
know where the T-DISK area is defined. They cannot issue a QUERY ALLOC
TDISK or QUERY TDISK command. T-DISK's can be placed anywhere, so
security by obscurity. I know that last comment won't fly with
auditors, which is what this whole curiosity going anyway. The auditor
On 9/17/09 5:18 PM, Alan Altmark alan_altm...@us.ibm.com wrote:
If I get my way, ENABLE CLEAR_TDISK will become the default and you won't
be able to change it. :-)
Want a requirement? 8-)
-- db
: Re: TDISK and SYSTEM CONFIG question.
As far as I know, without Clear_Tdisk, CP still formats the first cylinder of a
T-disk, so ACCESS will always fail even if you'd get a T-disk at the same place
as the previous user. But, with DDR or alike one could still find raw data on
other cylinders
I seem to remember a thread from long ago that discussed
unchangeable defaults. :-)
Original message
Date: Thu, 17 Sep 2009 17:18:30 -0400
From: Alan Altmark alan_altm...@us.ibm.com
Subject: Re: TDISK and SYSTEM CONFIG question.
To: IBMVM@LISTSERV.UARK.EDU
On Thursday, 09
You use STOP to avoid new stuff gets placed on the affected disk (TDISK,
Page, Spool). When new stuff is welcome again, you use START. To have CP
read the allocation map, an ATTACH to SYSTEM needs to be done, and that's
impossible when the disk is still attached to SYSTEM.
2009/9/16 Schuh
@LISTSERV.UARK.EDU
Subject: Re: Adding TDISK
You use STOP to avoid new stuff gets placed on the affected disk (TDISK, Page,
Spool). When new stuff is welcome again, you use START. To have CP read the
allocation map, an ATTACH to SYSTEM needs to be done, and that's impossible
when the disk
There is an option in the SYSTEM CONFIG file to clear the T-DISK. It is
in the FEATURES list and CLEAR_TDISK can be either ENABLED or DISABLED.
The manual states that it clears only cylinder 0 (zero) or the first
eight blocks on the temporary minidisk when it detaches the minidisk. Do
they mean
from SYSTEM and reattach it. Immediately enter Q ALLOC TDISK
and you'll see that all space is in use. Issue it a few times over the
next minute or two, and you'll see the space free up as it's cleared.
Dennis O'Brien
My computer beat me
On Wednesday, 09/16/2009 at 07:14 EDT, Gentry, Stephen
stephen.gen...@lafayettelife.com wrote:
Further, and in the same manual, it states that you can clear each
T-DISK
before it is reassigned. It depends on your point of view but this
seems
contradictory. Clear, in my opinion, means
How I start TDISK? The following is the procedure I followed. Any
help is appreciated. Thanks.
I did a CPFMTXA ALLOCATE on my 54BRES volume with the following command:
CPFMTXA 123 54BRES ALLOCATE
TDISK 1325.600
END
Result:
CYLINDER ALLOCATION CURRENTLY IS AS FOLLOWS
...@infocrossing.com wrote:
How I start TDISK? The following is the procedure I followed. Any
help is appreciated. Thanks.
I did a CPFMTXA ALLOCATE on my 54BRES volume with the following command:
CPFMTXA 123 54BRES ALLOCATE
TDISK 1325.600
END
Result:
CYLINDER ALLOCATION CURRENTLY
@LISTSERV.UARK.EDU
Subject: Re: Adding TDISK
Unfortunately - I don't believe you can get zVM to reread the allocation table
unless you detach/attach.. which you obviously can't do with your SYSRES.. so
you'd have to re-IPL to get VM to see it...
Scott
On Tue, Sep 15, 2009 at 3:37 PM, Wandschneider
PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: tdisk ?
There was a tdisk module a few years ago which attempted to link access
preformatted tdisk space set up as minidisks belonging to a dummy
userid. Only when none were available did it resort to defining and
formatting system tdisk space
I seem to recall using z/vm in the late 80's and there being a exec called
tdisk to create a temporary disk under cms. Is that available anywhere?
Thanks
Lionel B. Dyck, Consultant/Specialist
Enterprise Platform Services, Mainframe Engineering
KP-IT Enterprise Engineering, Client and Platform
:52 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: tdisk ?
I seem to recall using z/vm in the late 80's and there being a
exec called tdisk to create a temporary disk under cms. Is that
available anywhere?
Thanks
Yes but if it was an EXEC it isn't anymore to my knowledge. TDISK is
now done as follows
define tdisk 3390 as F01 cyl 100
devtyp cuu
You then have to format it using the regular format command.
Steve G.
From: The IBM z/VM
Subject
Re: tdisk ?
On Wed, 26 Sep 2007 09:51:33 -0700 Lionel B. Dyck said:
I seem to recall using z/vm in the late 80's and there being a exec
called
tdisk to create a temporary disk under cms. Is that available anywhere?
I will send Lionel my tdisk.exec and vdisk.exec for virtual disk
IBMVM@LISTSERV.UARK.EDU
09/26/2007 09:58 AM
Please respond to
The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU
To
IBMVM@LISTSERV.UARK.EDU IBMVM@LISTSERV.UARK.EDU
cc
Subject
Re: tdisk ?
On Wed, 26 Sep 2007 09:51:33 -0700 Lionel B. Dyck said:
I seem to recall using z/vm in the late 80's
David
-Original Message-
From: The IBM z/VM Operating System on behalf of Dave Jones
Sent: Wed 9/26/2007 4:31 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: [IBMVM] tdisk ?
Don't forge that some DASD space needs to be set aside for T-DISK usage
on CP-owned volumes before these execs can
There was a tdisk module a few years ago which attempted to link access
preformatted tdisk space set up as minidisks belonging to a dummy
userid. Only when none were available did it resort to defining and
formatting system tdisk space. It wouldn't be that difficult to
replicate the function
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