Dave:
I will venture to say that the PDSE is quite a bit like the CMS minidisk
file structure. I base this on an implementation of the CMS file system I
created back in the early '80s while at IBM in Poughkeepsie. It was intended
to support CMS running in a virtual machine environment (under SIE) in a TSO
address space. The prototype, although it worked as planned, never saw the
light of day as a product, although at one point we had staffed up two
development teams to produce it.
The file system was implemented using VSAM CI access and was exactly like a
CMS minidisk when viewed internally. It used a bit map for block (CI) access
control and the directory was just another file (and was capable of
extending, as needed). I contend that both the
PSDE and the Unix HFS file are based on that prototype's design.
Mike Myers
Mentor Services Corporation
----- Original Message -----
From: "Dave Jones" <[EMAIL PROTECTED]>
To: <IBMVM@LISTSERV.UARK.EDU>
Sent: Thursday, August 10, 2006 4:53 PM
Subject: Re: PDSE Support in CMS
Isn't the PDS(E) file store somewhat like a CMS minidisk file structure,
in that there are two directories at the beginning of the space, and files
can be added, deleted and modified *without* the need for a separate
compression step every now and then?
DJ
Jim Bohnsack wrote:
Christine--I'm not an MVS type, so I don't really know much about MVS's
PDS or PDSE support. I have heard, tho, that the PACKLIB support in
FCOPY from the VM download page can be, in some ways, thought to be
similiar (is that enough of a disclaimer?) to an MVS PDS. I've used
FCOPY and the more recently added PACKLIB feature ever since it became
available in IBM internally and now from the download page. You can
stuff anything you want into a PACKLIB, including duplicate fileid's.
You get anywhere from a 5-10 : 1 compression ratio, at least for normal,
unpacked files. You cannot put programs into a PACKLIB and execute from
there. You would have to extract a module or exec to have something to
execute.
To answer your original question, no there has been nothing added to VM
in this regard since you looked at the VM/ESA 1.2 level.
Jim
At 01:29 PM 8/10/2006, you wrote:
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Is there support for PDSE in CMS these days...?
I found in the archives back from 1995 that there was no support in CMS
for
PDSE's (the "new" PDS format for MVS datasets).
That was on VM 1.2 I believe. I can't find that anything has changed
since
then. Has it?
Thanks!
Christine Brogan - TPF/VM Systems Support
Information Technology Services Americas
Phone: 623-505-5366, Cell: 623-512-5883, IBM tieline 273-4647
Email: [EMAIL PROTECTED]
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Is there support for PDSE in CMS these days...?
I found in the archives back from 1995 that there was no support in CMS
for PDSE's (the "new" PDS format for MVS datasets).
That was on VM 1.2 I believe. I can't find that anything has changed
since then. Has it?
Thanks!
Christine Brogan - TPF/VM Systems Support
Information Technology Services Americas
Phone: 623-505-5366, Cell: 623-512-5883, IBM tieline 273-4647
Email: [EMAIL PROTECTED]
--0__=08BBFB55DFCC43078f9e8a93df938690918c08BBFB55DFCC4307--
Jim Bohnsack
Cornell Univ.
(607) 255-1760
