SVC 34

[Ward, Mike S]

Can anyone please tell me where the description on how to use SVC's in z/OS is.

I remember back when there was a book devoted to MVS svc's and the parameters required to call them. I can't seem to find one for z/OS.

Specifically SVC 34.

Any help appreciated.

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[Gates, Guy]

I will be out of the office from 1/16 returning on 1/21. If you need immediate assistance, Please contact the Help Desk. Thank You...Guy Gates

[Ray Overby]

Assuming you meant 34 decimal:

z/OS V1R13.0 MVS Diagnosis: Reference: 1.4.3.35
Document Number: GA22-7588-17


1.4.3.35 SVC 34 (0A22)


MGCR|MGCRE|QEDIT macros. If you search IBM books you should find doc on
each......


Ray Overby
Key Resources, Inc.
Ensuring System Integrity for z/Series^(TM)
www.kr-inc.com
(312)574-0007

[Alan Atkinson]

http://publib.boulder.ibm.com/infocenter/zos/v1r11/index.jsp?topic=/com.ibm.zos.r11.ieav200/svc34.htm

[Lennie J Dymoke-Bradshaw]

Mike,

Try the Authorised Assembler Reference - LLA-SDU (SA22-7611-13) and look
at the MGCR and MGCRE macros.
The SVC descriptions are in the MVS Diagnosis reference manual.
(GA22-7588-16).

Lennie Dymoke-Bradshaw MBCS CITP
Accredited Senior I/T Specialist, System z, Security and Cryptography, IBM
Software Group
Mail: Lennie J Dymoke-Bradshaw/UK/IBM@IBMGB or
Lennie_...@uk.ibm.com
There are two types of people in the world; those who have been hacked,
and those who will be hacked.

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number
741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU

[Edward Jaffe]

On 1/16/2013 2:26 PM, Ward, Mike S wrote:
> Can anyone please tell me where the description on how to use SVC's in z/OS is.
>
> I remember back when there was a book devoted to MVS svc's and the parameters required to call them. I can't seem to find one for z/OS.

MGCR/MGCRE is described in Authorized Assembler Services Guide and Reference.

--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
http://www.phoenixsoftware.com/

[Ward, Mike S]

Thanks to all who replied. Gotem.

[Lizette Koehler]

z/OS V1R12.0 MVS Diagnosis Reference

Lizette

> -----Original Message-----
> From: IBM Mainframe Assembler List
[mailto:ASSEMBL...@LISTSERV.UGA.EDU]

> On Behalf Of Ward, Mike S
> Sent: Wednesday, January 16, 2013 3:26 PM
> To: ASSEMBL...@LISTSERV.UGA.EDU
> Subject: SVC 34
>

[Peter Relson]

>Can anyone please tell me where the description
>on how to use SVC's in z/OS is.

No such description is really needed. You do not use SVC's. You use
services. A service may choose to use an SVC as its method of getting
control (just as it may use a PC or a BALR or a BASSM).

If you were intending to write your own SVC routine that might be a
different matter, and you would be strongly discouraged from doing so.
If you were asking something like "I see an SVC issuance in a trace, what
service was it?", then the diagnosis reference mentioned by Ray Overby can
help.

Peter Relson
z/OS Core Technology Design

[Lindy Mayfield]

Is there ever a "need" to write an SVC? Or to put it another way, is there sometimes a need to get OS services from a problem state program like in an SVC? And if so, are PC routines the new way?

Were once SVC's ok, and now they are not preferred?

Just curious is all.

Thanks!
Lindy

-----Original Message-----
From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU] On Behalf Of Peter Relson
Sent: Thursday, January 17, 2013 2:45 PM
To: ASSEMBL...@LISTSERV.UGA.EDU

[Gerhard Postpischil]

On 2/6/2013 4:26 PM, Lindy Mayfield wrote:
> Is there ever a "need" to write an SVC? Or to put it another way, is there sometimes a need to get OS services from a problem state program like in an SVC? And if so, are PC routines the new way?

If you are writing new code, PC is the preferred method. If you just
want to experiment, writing an SVC is interesting and educational.

> Were once SVC's ok, and now they are not preferred?

When the S/360 was new, the available systems offered no practical way
to perform some authorized functions from applications except by SVC, or
the less desirable method of source changes to the system.

Many installations implemented SVCs that changed a program state to key
0 or supervisor state, something that presented a security exposure. IBM
eventually introduced authorized programs and the MODESET facility, then
later the PC and related instructions.

Gerhard Postpischil
Bradford, Vermont

[Peter Relson]

>Is there ever a "need" to write an SVC?

There are few reasons that come to mind, and none that
are likely truly needed outside of the operating system.

>Or to put it another way, is there sometimes a need to get
>OS services from a problem state program like in an SVC?

Yes

>And if so, are PC routines the new way?

If by "new" you mean "for 30+ years", yes
(25 years or so if you want a stacking PC).

>Were once SVC's ok, and now they are not preferred?

PC did not used to exist initially. SVC was the only choice at that time.

[John Gilmore]

The question

| Were once SVC's ok, and now they are not preferred?

could be colored naif, but it is an entirely legitimate one, and the
answer is yes.

John Gilmore, Ashland, MA 01721 - USA

[Lindy Mayfield]

If that color is mauve, and if a person such as I who asks na�ve questions is indeed na�f, then point taken. :-)

-----Original Message-----
From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU] On Behalf Of John Gilmore
Sent: Thursday, February 07, 2013 3:08 PM
To: ASSEMBL...@LISTSERV.UGA.EDU
Subject: Re: SVC 34

[David Stokes]

It's just JG's usual style, first the insult, then the condescending remark, and if you stay with it a (maybe*) useful comment ("yes"). (*If it hadn't been said several times already.)

It's always somehow wonderful to hear that there are still people now trying to learn this stuff.


-----Urspr�ngliche Nachricht-----
Von: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU] Im Auftrag von Lindy Mayfield
Gesendet: Donnerstag, 7. Februar 2013 20:34
An: ASSEMBL...@LISTSERV.UGA.EDU
Betreff: Re: SVC 34

[Hall, Keven]

Ah yes, but who can match the weary erudition embodied in his "curmudgeon's curmudgeon" style?

Keven Hall

[Lindy Mayfield]

Mr. Gilmore I would consider a "friend" until he tells me otherwise. For each of his erudite tit there is my inane tat. It takes two to tango. Piazzolla is my favorite.

Cannatello tells how to write an SVC, and his book is relatively new, and mentions nothing about PC routines. So my question isn't really "in vento et rapida scribere oportet aqua."

Lindy

[Sam Siegel]

On Thu, Feb 7, 2013 at 3:43 PM, Lindy Mayfield <Lindy.M...@sas.com>wrote:

> Mr. Gilmore I would consider a "friend" until he tells me otherwise. For
> each of his erudite tit there is my inane tat. It takes two to tango.
> Piazzolla is my favorite.
>
> Cannatello tells how to write an SVC, and his book is relatively new, and
> mentions nothing about PC routines. So my question isn't really "in vento
> et rapida scribere oportet aqua."
>
>

Regardless of the wind and water; Relson says write PC routines instead of
SVCs. And he is without a doubt and authority on this topic.

> Lindy
>
> -----Original Message-----
> From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU]
> On Behalf Of Hall, Keven
> Sent: Friday, February 08, 2013 12:01 AM
> To: ASSEMBL...@LISTSERV.UGA.EDU
> Subject: Re: SVC 34
>
> Ah yes, but who can match the weary erudition embodied in his
> "curmudgeon's curmudgeon" style?
>
> Keven Hall
>
> -----Original Message-----
> From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU]
> On Behalf Of David Stokes
> Sent: Thursday, February 07, 2013 13:52
> To: ASSEMBL...@LISTSERV.UGA.EDU
> Subject: Re: SVC 34
>
> It's just JG's usual style, first the insult, then the condescending
> remark, and if you stay with it a (maybe*) useful comment ("yes"). (*If it
> hadn't been said several times already.)
>
> It's always somehow wonderful to hear that there are still people now
> trying to learn this stuff.
>
>

> -----Ursprüngliche Nachricht-----

> Von: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU]
> Im Auftrag von Lindy Mayfield
> Gesendet: Donnerstag, 7. Februar 2013 20:34
> An: ASSEMBL...@LISTSERV.UGA.EDU
> Betreff: Re: SVC 34
>

> If that color is mauve, and if a person such as I who asks naïve questions
> is indeed naïf, then point taken. :-)

[retired mainframer]

My copy of Cannatello is dated 1999. A lot has changed in 14 years. And
the index shows more than a few pages dealing with the PC instruction and PC
routines. I didn't think water cooled machines were still supported.

:>: -----Original Message-----
:>: From: IBM Mainframe Assembler List [mailto:ASSEMBLER-
:>: LI...@LISTSERV.UGA.EDU] On Behalf Of Lindy Mayfield
:>: Sent: Thursday, February 07, 2013 3:43 PM

:>: To: ASSEMBL...@LISTSERV.UGA.EDU
:>: Subject: Re: SVC 34

:>:
:>: Cannatello tells how to write an SVC, and his book is relatively new,

[Lindy Mayfield]

That is double what Mr. Relson said, and people still talk about how great Canetello's books is.

I asked a simple, honest question, and people turn it into some sort of attack on ... I'm just too easy. I am just curious. Take whatever shots at me you like if that make you feel good about yourself.

Lindy

[Sam Siegel]

On Thu, Feb 7, 2013 at 5:45 PM, Lindy Mayfield <Lindy.M...@sas.com>wrote:

> That is double what Mr. Relson said, and people still talk about how great
> Canetello's books is.
>
> I asked a simple, honest question, and people turn it into some sort of
> attack on ... I'm just too easy. I am just curious. Take whatever shots
> at me you like if that make you feel good about yourself.
>

Lindy - I'm not taking a shot at you. If it came across like that, my
apologise.

The CBT has example PC routines. You may find these helpful.

[John Gilmore]

What I wrote was:

| The question

|| Were once SVC's ok, and now they are not preferred?

| could be colored naif, but it is an entirely legitimate one, and the
answer is yes.

It reflected my view that, while Lindy's question had been
condescended to, it was in fact an "entirely legitimate" one.

This view, expressed umambiguously, was somehow transmogrified into a
vehicle of insult followed by condescension. It was neither, and a
neutral native English speaker would not have judged it to be either.

Let me therefore make my advice more specific. SVC routines are
lumbered with a long history of machinery---types, transient areas,
segmentation into 4096-byte pieces, etc., etc,---that is now
irrelevant. If you have SVC routines that do something that is at
once useful and secure, maintain them; if instead you are setting out
to do something ab initio, use PC routines instead. Finally, try to
consider, dispassionately, the uncomfortable question whether you know
enough to do what you are proposing to do safely and securely.

I entirely agree with the substance of what Peter Relson has been
saying (if not always with the wording of his strictures). Services
should be implemented only by people who know what they are doing,
i.e., by the over-competent. Most of the user SVC routines I have
examined are 1) dispensable, 2) ill-conceived, and 3) insecurely
implemented.

[B V]

How do I get off this listserv?

--
Cheers!

Bernard "Benny" Villegas
The University of Georgia
Biomedical Engineering & Biochemistry and Molecular Biology
Undergraduate Biomedical Science Researcher
Cell: 770-344-9080

[David de Jongh]

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-----Original Message-----
From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU]
On Behalf Of B V
Sent: Thursday, February 07, 2013 9:13 PM
To: ASSEMBL...@LISTSERV.UGA.EDU
Subject: Re: SVC 34

[Rob Scott]

Lindy,

Implementing a PC routine requires a little bit more planning and consideration than the SVC method.

For starters, you are going to need a resource-owning address space to own the linkage index.

You are going to have to understand the implications of providing the service you intend and consider carefully the normal (and abnormal) removal of the same.

Is the service going to be available to all address spaces or just a select few?

I suggest reading up on any of the following you are not familiar with :

MVCDK and MVCSK
Resource managers
ASN and LX reuse
System integrity

Most of the installation-written SVCs I have come across have been more of a "smash and grab" solution.
The SVCs were "easier" to write as there was less baggage to accompany them and they could be expressed in a single program.
Some of the installation-written SVCs I have come across have had system integrity holes so big you could drive a truck through.

Personally, I would not even consider writing an SVC these days.

Strangely, some sites still have objections to any new address spaces appearing on the system, even if all it does is sit there and quietly own stuff.

Rob Scott
Lead Developer
Rocket Software
77 Fourth Avenue . Suite 100 . Waltham . MA 02451-1468 . USA
Tel: +1.781.684.2305
Email: rsc...@rs.com
Web: www.rocketsoftware.com

-----Original Message-----
From: IBM Mainframe Assembler List [mailto:ASSEMBL...@LISTSERV.UGA.EDU] On Behalf Of John Gilmore
Sent: 08 February 2013 03:04
To: ASSEMBL...@LISTSERV.UGA.EDU
Subject: Re: SVC 34

[Lindy Mayfield]

I was out of line. My apologies to the group.

[Edward Jaffe]

On 2/7/2013 5:24 PM, retired mainframer wrote:
> I didn't think water cooled machines were still supported.

zEC12 can be water cooled for those that wish to save energy in their data center.