Re: z/OS equivalent to z/VM's Link Aggregation

[Christian Borntraeger]

Am 08.12.22 um 17:44 schrieb Jim Elliott:

I am sure that z/OS must provide a function equivalent to z/VM's Link
Aggregation (where you can share physical OSA ports in a VSwitch), but lots
of Google searches are not helping me. Any suggestions?



Link aggregration is on layer2 (ethernet) and used by Linux/zVM while z/OS talks
to OSA in layer3. So I guess the equivalent would be VIPA.

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Re: Software Delivery on Tape to be Discontinued

[Christian Borntraeger]

On 03/27/2018 07:09 PM, David Boyes wrote:
> On 3/27/18, 12:02 PM, "IBM Mainframe Discussion List on behalf of Paul 
> Gilmartin"  000433f07816-dmarc-requ...@listserv.ua.edu> wrote:
> 
>> On Tue, 27 Mar 2018 13:57:45 +, David Boyes wrote:
>>> ... I think the bigger issue is that IBM no longer makes a device that can 
>>> directly read the DVD media from the mainframe without involving any other 
>>> system.. 
>> HMC?  VM?  Linux?  "no longer"?
> 
> The HMC DVD is not directly accessible to any operating system as a device 
> with VM or Linux, and the interface to it is not a published one. 

For Linux there is at least some support. There is the hmcdrv module and the 
hmcdrvfs fuse tool in the s390-tools. I do not know how well this works and
if I remember correctly you have to have the LPAR authorized for that access.
I think it was authorized after you have done a load from DVD via HMC. I have
no idea if there are other means to authorize an LPAR.

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Re: diagnose 8 / interesting dilemma

[Christian Borntraeger]

On 10/17/2016 08:23 AM, Paul Schuster wrote:
> I am issuing DIAGNOSE 8 on my z/os image under VM (z/vm) to do a QUERY 
> VIRTUAL DASD.  It works—up to a certain point:
> 
> The QUERY VIRTUAL DASD command returns (for me) 38617 (decimal) bytes, 
> according to the CC=0 after the DIAGNOSE 8 command.  My buffer is large 
> enough to accommodate this.  I have tried several different sub-pools of 
> storage.  I PGSER FIX the buffer pages.  I do a SYSEVENT DONTSWAP.  I do a 
> LRA of the virtual address of the start of the buffer.  The DIAGNOSE 
> completes CC=0. But, in my buffer, I am only seeing the first page (4095) 
> bytes of the output.  
> 
> My question: I don’t see any documented restriction in the VM manuals that 
> limits the DIAGNOSE 8 output buffer to 4K (rather the limitation is the 
> architecture limit depending on your amode.) The z/vm manuals say the buffer 
> can cross page boundaries.  So is there a way to force the real storage 
> addresses of the page-fixed pages to be consecutive?  According to the 
> diagnose 8 doc., the buffer needs to be in guest-real storage, hence the LRA. 
>  And it is working for the first 4k page.
> 
> Thank you for any insight you can provide. 

As you already guessed, the memory you get is virtual, so the pages are not 
consecutive. The LRA will give you the address of the first page, but the 2nd, 
3rd and so on will be somewhere else. Please note that your code will even 
cause random memory overwrites in your z/OS as the diag8 will write to the real 
address of your LRA, the real address of your LRA+4096 and so on.

I do not know if there is an interface to get consective real memory as I am 
not an Z/OS expert. 

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Re: Dynamic CPU ADD to a z/OS lpar

[Christian Borntraeger]

On 05/12/2016 08:33 AM, Vernooij, CP (ITOPT1) - KLM wrote:
> I am quite sure, at least for the z196, that you can online config CPs 
> online, if they have been defined as Reserved. To do so, you must change the 
> LPAR profile and de/reactivate the LPAR. So dynamically, in a running z/OS: 
> no.
> 
> Kees.

With all newer machines there is a "logical CPU add" that can add CPUs even if 
reserved == 0.
You will be asked if that should happen for the running system, the profile or 
both.

These CPUs appear then as reserved and can be configured on from the operating 
system. At least
that works with Linux and a z196 and IFLs, so I assume z/OS should be able to 
do then same.

Christian

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