It’s allocated 2 primary cylinder 2 secondary cylinder
So
XR. 5,5
ICM 5,B’0111’,JFCBPQTY
XR. 6,6
ICM 6,B’0111’,JFCBSQTY
MH. 6,=H’15’
AR. 5,6
MH 5,=H’15’
XR. 4,4
M. 4,=F’56664’
ST. 5,TOTBYTES
I think the max possible is totbytes
Based that it was allocated in cylinders not tracks
For tracks don’t need MH 5,=H’15’
I think this is right it’s max possible probably less then
On Tue, Jun 30, 2026 at 11:19 AM Lennie Bradshaw <
[email protected]> wrote:
> It may more sense for you to determine the number of tracks and then
> simply multiply by maximum track capacity of 56664 (for 3390 devices).
> Do you have a copy of GX26-4577-03 (or later)?
>
> Lennie
>
> -----Original Message-----
> From: IBM Mainframe Discussion List <[email protected]> On Behalf
> Of Joseph Reichman
> Sent: 30 June 2026 16:14
> To: [email protected]
> Subject: Re: Net bytes per track
>
> Since I would rather high mean I want max possible
>
> I multiply if it’s cyl by 15 for secondery by 16 And then by 56664 it’s
> impossible to use more than allocated
>
>
>
> Get Outlook for iOS<https://aka.ms/o0ukef>
> ________________________________
> From: IBM Mainframe Discussion List <[email protected]> on behalf
> of Lennie Bradshaw <[email protected]>
> Sent: Tuesday, 30 June 2026 11:10:34
> To: [email protected] <[email protected]>
> Subject: Re: Net bytes per track
>
> Also, some data sets can have variable block sizes. They can also have
> RECFM=U like load libraries, so that the block sizes are not predictable. I
> think the binder uses 32K blocks and then fills the track with shorter
> blocks.
>
> Lennie
>
> -----Original Message-----
> From: IBM Mainframe Discussion List <[email protected]> On Behalf
> Of Michael Oujesky
> Sent: 30 June 2026 15:46
> To: [email protected]
> Subject: Re: Net bytes per track
>
> Not quite correct. SMS compressed files super-block and write full tracks
> of data. BLKSIZE becomes logical (i.e. the buffer size of data used
> between the applcation and the SAM access method.
>
> See SMF14CIS in the 14/15 SMF record for the actual physical size on the
> track.
>
> Michael
>
> At 08:19 PM 6/29/2026, Michael Watkins wrote:
> >Content-Transfer-Encoding: base64Yes, 56664 bytes per track on a 3390,
> >but the maximum z/OS BLKSIZE is 32,760 bytes and only one block will
> >fit on a track.
> >
> >To maximize the amount of data on a track, half-track blocking is
> >typically used. There is a 668-byte inter-record gap on a native 3390
> >(platters on a spindle), which has been replicated on RAIDed FBA
> >devices in modern DASD architecture. This means there is a maximum
> >half-track BLKSIZE of 27998 bytes since 668+(2x27998)=56664.
> >
> >For a data set with 80-byte records, this means half-track blocking
> >means a 27920-byte BLKSIZE since 349 x 80 = 27920 and there isn't room
> >in
> >27998 for the 350th 80-byte record.
> >
> >Also keep in mind that z/OS will append 32 bytes onto each block when
> >DSNTYPE=EXTENDED is specified, meaning less space for data records is
> >available.
> >
> >
> >
> >-----Original Message-----
> >From: IBM Mainframe Discussion List
> ><[email protected]> On Behalf Of Joseph Reichman
> >Sent: Monday, June 29, 2026 8:01 PM
> >To: [email protected]
> >Subject: Re: Net bytes per track
> >
> >CAUTION: This email originated from outside of the Texas Comptroller's
> >email system.
> >DO NOT click links or open attachments unless you expect them from the
> >sender and know the content is safe.
> >
> >I keep on seeing from AI 56,664 bytes per tack for 3390 pack how is
> >that determined
> >
> >
> >Joe Reichman
> >
> >On Mon, Jun 29, 2026 at 8:58 PM Attila Fogarasi <
> >[email protected]> wrote:
> >
> > > The net bytes (i.e. longest record you can write to that track)
> > > varies by access method as there is overhead (control bytes).
> > > TRKCALC is provided to compute the largest record which can fit on a
> > > track (using EXCP), see
> >B‚‡GG3¢ò÷W&ÆFVfVç6Ræ6öÒ÷c2õõö‡GG3¢ð/www.ibm.com/docs/en/zos/3.2.0?topi
> > > c=instructions-performing-track-calculations-trkcalc-macro__;!!JJZmG
> > > cL
> > > PLA!f8gIQp2WmnK5aJpNmmtG4m8kLdObQsseimGBKGffYscn-nyU3MS1l3Ja7JSZEZ7c
> > > 6P
> >”[XÕ “VŽNP MÓYUÎS“ZÑÌ ÜÖ[^™ÖL€g$
> > >
> > > Unless you are using EXCP the hardware track capacity is irrelevant,
> >HXØÙ\ÜÈY]Ù\ÙYÚ[]@rmine the actual bytes per track (and
> > > varies by BLKSIZE).
> > >
> > > On Tue, Jun 30, 2026 at 10:35 AM Joseph Reichman <
> > > [email protected]> wrote:
> > >
> > > > Would anyone know how to get the net bytes per track for a 3390
> > > >
> > > H]™H™Y[ˆ\Ú[™È] @pe ddname,buffer,devtab
> > > >
> > > B‚âv†W&R'VffW"—232 byte output field
> > > >
> > > ]]ÙY\ÈÛˆÛÛZ[™È˜XÀk with the overhead of 58,864
> > > >
> > > H[šÈH™]@s 56,664
> > > >
> > > HÛÝ[ZÙHÈÙ]]šYÝ\™H›Ùܘ@mmatically instead of hard
> >ˆÛÙ[™Â‚—@Ð €ø4(ø€ø Phanks
> > > >
> > > KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK@---------------------------
> >ˆKH›ÜˆP“KSPRSˆÝXœØÜšX€e / signoff / archive access instructions,
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> > > IBM-MAIN
> > > >
> > >
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