MVS/370, at least, used track overflow heavily. It would not run on Hercules until we got that feature right.
On Fri, Aug 29, 2025 at 4:02 AM Radoslaw Skorupka < [email protected]> wrote: > AFAIK the track overflow feature is no longer supported. For years. > Actually it is one of the things I have never met in real world but it > was mentioned in the documentation. Like CVOL. > > Regarding track overflow - does it mean the following? > 1. Block is being written to track. However the block is too long, so > the remaining part is written on another track. > 2. The tracks have to be consecutive (or not?) > 3. The block can occupy one, two or more tracks. Or only one or two? > 4. Track space after last part of the block cannot be used by any other > block, that means it remain unused. > > BTW: Is there any (historical) documentation about track overflow? Just > curious, obviously it has no practical meaning nowadays. ;-) > > -- > Radoslaw Skorupka > Lodz, Poland > > > > W dniu 28.08.2025 o 23:32, Mike Schwab pisze: > > Devices with blocksizes under 32K have a feature called track overflow. > > When it reaches the end of track the block is continued on the next > track, > > and the remainder after the last partial block is unused. > > > > Linkage editors will determine the remaining space on a track and write > the > > highest multiple of 1K that will fit. Compress in place object modules > > reblock to 1KB multiples. > > > > I assume VB/FB members are reblocked by compress in place, but not sure. > > > > On Tue, Aug 26, 2025 at 7:22 AM Paul Edwards < > > [email protected]> wrote: > > > >> On Tue, 26 Aug 2025 12:16:06 +0000, Seymour J Metz <[email protected]> > wrote: > >> > >>> My recollection is that COPYMOD is only valid for DASD-DASD. > >> I only need DASD to DASD. I only need to transport a single > >> load module. > >> > >> And I (basically) have control over the linker (pdld) that will > >> directly produce IEBCOPY (basically) format (artificially > >> produce an unloaded load module). > >> > >> Load modules only exist in DASD, so that's not a problem. > >> > >> It will look like it has been unloaded from a DASD - but the > >> type of DASD is up for grabs. > >> > >> Note that this already exists, but we're trying to clarify what > >> the device characteristics should ideally be for general > >> purpose use. I was thinking 1 record per track, 1 head and > >> up to 65536 cylinders giving a maximum load module size > >> of 384 MiB (with 6144-byte blocks), which is plenty. > >> > >> But the IEBCOPY manual has a different artificial device. > >> But they have a different objective than transporting a > >> single load module. > >> > >> BFN. Paul. > >> > >> ---------------------------------------------------------------------- > >> For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO IBM-MAIN > >> > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- Jay Maynard ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
