Re: IBM Power Systems enhances its server and I/O options

Sue really covers this well here but a couple other notes.

First there are features in the disk units that IBM i exploits and that is IBM owned code. If those features are not there that's a problem, hence the support for only specific VPD as Sue indicated.

Second, when is the last time you updated the firmware of the drives, RAID cards, SAS back-planes, etc on your IBM i Partitions? What's that, you say "Never?" That is incorrect. Potentially you do this with every PTF! You do PTFs you IPL your machine sees a drive with down level firmware, it updates said firmware, you sip your coffee. It's a great deal! (Side note: This is why 5887 drawers are supported only in Mode 1 with IBM i. See if you can figure out why... :-) )

Years ago there we some vendors selling 'plug compatible drives' for then 'AS/400' machines. Customer upgrades to newest release (seem to recall V4R4) and craters the machine. Why? The new release updated the firmware on those drives. Since they were not IBM Drives the new firmware destroyed them. The vendor merely said: "We never said we were compatible with the NEXT release, only the one you were running when you purchased them!"

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 2/16/2017 9:12 AM, Sue Baker wrote:

Jonathan Wilson
<piercing_male@xxxxxxxxxxx> wrote on
Thu, 16 Feb 2017 13:19:32 GMT:

This raises a question in my mind. Does the I have "hardcoded"
(for want of a better term) acceptable disks? Or can it accept
any disk that can be connected to it just as long as the
interface/protocol matches?

All operating systems require device drivers to recognize disk.
IBM i only recognizes specific devices containing specific VPD
(vital product data) which is on each disk device.

To expand. Are the cables/protocols/connectors/backplane
industry standard in that they use the SAS interface and the
SAS command set?

Yes, industry standards are used.

Following that, if SAS, does the SAS also
include the sata tunnelling protocol so that it can accept
sata disks?

No, there are no SATA disk with the appropriate VPD.

That then leads on to the question, if the
cables/interfaces are industry standard... is it possible to
"build your own" expansion box by running the cables into an
external drive draw and shoving a load of larger IBM LFF's or
commodity "near line" SAS's in there?

No

Obviously if the drives/interfaces are fibre channel then
thats a whole different ballgame (interposer cards ;-).

Now I realise that a person buying an I is likely to want all
the advantages that come with the box, such as reliability and
the ability of the disk system to keep the processor busy and
a host of other "it just does" features... but as a nerd with
a home built multi-TiB media server running linux who loves
the technicalities, and nitty-gritty, of both hardware and
software the details and "I wonder if I could just..."
questions and answers fascinate me.

You can try, but likely will end up with a bunch of hardware not
recognized by either Power Systems firmware and/or IBM i.