This is a really difficult task as I see because of the  blocking factor

I decided the best solution is to go back to my roots in computer science

Since I am a Dinosaur that’s before OO

I mean Knuth

I am going to use a linked list

I cannt create a cell pool because each record size is different in a vb
file

I am hoping not to fragment storage

But going to give this a shot

Thank you




On Tue, Jun 30, 2026 at 9:55 PM Mike Schwab <
[email protected]> wrote:

> Through the 3350 there were some programs that wrote full track R0
> records to get a slightly larger block.
>
> On Tue, Jun 30, 2026 at 7:19 PM Michael Watkins
> <[email protected]> wrote:
> >
> > I think I hear what you're saying - that a 32720-byte record might
> occupy far few bytes when compressed and several could fit into a
> 56632-byte physical record. I concede that SMF uses them,  but unless
> you're IBM, (or another software vendor) you're not writing a 65632-byte
> physical record. This is not available to someone writing a problem program.
> >
> > -----Original Message-----
> > From: IBM Mainframe Discussion List <[email protected]> On
> Behalf Of Michael Oujesky
> > Sent: Tuesday, June 30, 2026 6:39 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.
> >
> > Due to compression, yes there could be more than one 32720 byte logical
> record in the 56632 byte
> > physical record.   Even if they were fixed length 32720 records.
> >
> > Michael
> >
> > At 06:04 PM 6/30/2026, Seymour J Metz wrote:
> > >Content-Transfer-Encoding: base64No. But not all records are 32K in the
> > >noormal run of things.
> > >
> > >
> > >--
> > >Shmuel (Seymour J.) Metz
> > >https://urldefense.com/v3/__http://mason.gmu.edu/*smetz3__;fg!!JJZmGcLP
> > >LA!ffzBLup1PnWeGv_oP4SB8byOd9J5Ff8umRy31Qljuae4YSldPom7vXRy-UxSnOzuD7LW
> > >CJqoLizjwVMd0Xrb_0t1iz4A2xha$ ×¢Ö·×  ×(tm)ִשְ×'×¨Ö¸× Öµ×oe ×-Ö·×(tm)
> > >� ֵ֣צַ×- ×(tm)ִשְ×'×¨Ö¸× ÖµÖ"×oe ×oeÖ¹Ö¥×
> > >×(tm)Ö°×©Ö·× ×§ÖµÖ¼Ö­×¨
> > >
> > >
> > >
> > >
> > >________________________________________
> > >From: IBM Mainframe Discussion List
> > ><[email protected] on behalf of Michael Watkins
> > ><[email protected]��[��Y\�^K�
> > >[�HÌOE��
> > >���HPM
> > >To: [email protected] <[email protected]>
> > >Subject: Re: Net bytes per track
> > >
> > >
> > >External Message: Use Caution
> > >
> > >
> > >I also notice that the LRECL is 32720 and the records (FB) do not
> > >appear spanned. Can there be more than one 32720-byte record in this
> > >56,632-byte physical block?
> > >
> > >-----Original Message-----
> > >From: IBM Mainframe Discussion List
> > ><[email protected]Û^�Z[f Of Michael Watkins
> > >Sent: Tuesday, June 30, 2026 5:18 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.
> > >
> > >Sure, since the 1970s VSAM physical records have not corresponed 1-to-1
> > >with the CI-size.
> > >Probably other access methods, too. That's just the one I'm keenly
> aware of.
> > >
> > >The URL you cite directs me to a section of 'DFSMS Using Data Sets'.
> > >For z/OS V3.2 (SC23-6855-70), this is p.386, 'Characteristics of
> > >compressed format data sets'. However, the table with the SMF report
> > >file is from another source. It has this line:
> > >
> > >ID      DSORG   RECFM   LRECL   BLKSIZE         SMF14CIS
> SMF14CMPTYPE
> > >14      PS      FB        80      32720          56632          3:ZEDC
> > >
> > >'SMF14CIS' is a field found within the SMF Type
> > >14 record that indicates the physical block size of an extended format
> > >data set. 56632 plus the
> > >32 bytes appended for extended formatting is 56664, the track size.
> > >Since creating these is '
> > >Nothing complex. Merely create the dataset with SMS compression.
> > >Allocation and the SAM access method takes care of the details', what
> > >allocation parameters are used to specify this extended format data set
> > >whose physical record consumes the entire track with no inter-record
> > >gapsB�B�B�KKKKSÜsY�[�[Y\��Y�KKKKKCB���om: IBM
> > >Mainframe Discussion List
> > ><[email protected]Û^�Z[�Ù^ZX�Y[�Z�\��CB��[�ï
> > >¿½Y\�^K�[�H�2026 4:38 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.
> > >
> > >Please see:
> > ><https://urldefense.com/v3/__https://www.ibm.com/docs/en/zos/3.2.0?topi
> > >c=sets-characteristics-compressed-format-data__;!!JJZmGcLPLA!dfwGSymF-D
> > >Pi6jbNV2JZPFANiX3GmcW3d-5nqWl679R_NRKSC_KL9t8J-StNr50aZ7fgZYLeeHPxyd5NW
> > >uJ-rTXdccGouSwF$
> > >�\�X�\�\�X��Ù^��\�\��Y�Ü>X]]H�]�@ IBM
> > >Documentation The data format for a compressed format data set consists
> > >of physical blocks whose length has no correlation to the logical block
> > >size of the data set in the DCB, DCBE, and the data set label. The
> > >actual physical block size is calculated by the system and is never
> > >returned to the user.
> > >However, the system maintains the user's block boundaries when the data
> > >set is created so that the system can return the original user blocks
> > >to the user when the data set is read.
> > >SMF report of such files:
> > >ID    DSORG    RECFM    LRECL    BLKSIZE    SMF14CIS    SMF14CMPTYPE
> > >
> > >14     PS       VBS     32760     32760       27966      2:TAILORED
> > >14     PS       VB       4096     32760       27966      2:TAILORED
> > >14     PS       FB         80     32720       56632      3:ZEDC
> > >14     PS       FB      32752     32752       27966      1:GENERIC
> > >Michael
> > >
> > >
> > >At 11:30 AM 6/30/2026, Michael Watkins wrote:
> > > >Please either expalin how to allocate an 'SMS compressed file with
> > > >super-blocks that write full tracks of data' or point to some IBM
> > > >documentation that explains this.
> > > >
> > > >I assume from the context of your previous remarks that 'full tracks
> > > >of
> > >]I�YX[��\�H\�H��[�ter-record gaps within the blocks; a
> > >���V�OMM���\��entially.
> > >B��v���B77V֭�r��W"&Wf��W26���V�G2F�n't
> > >make sense. Despite
> > > >decades of mainframe infrastructure experience, I've never heard of
> > >\Ë ]H�\�Z@nly don't know everything.
> > > >
> > > >-----Original Message-----
> > > >From: IBM Mainframe Discussion List
> > >P�KSPRS�T��ERV.UA.EDU> On Behalf Of Michael Oujesky
> > > >Sent: Tuesday, June 30, 2026 11:18 AM
> > > >To: [email protected]
> > >Subject: Re: Net bytes per track
> > > >
> > > >Nothing complex.  Merely create the dataset with SMS compression.
> > > >Allocation and the SAM access method takes care of the details.
> > > >
> > > >Check you 14/15 SMF records for the actual physical size of blocks on
> > > >DASD.  14/15 still have BLKSIZE, but is is now logical and not
> > >\�X�[�B�С5������4(�4(�� 10:49 AM 6/30/2026,
> Michael Watkins wrote:
> > > > �X\�\�mud. How do I define a data set using full tracks of
> > > > super-blocks using zEDC compressionÙ^��\��KHUP�@S
> > > > specifying
> > >��Q���\�\��[Û^�[]�HÈ(tm)H\��YÛ(tm)@d, but what
> > >allocation
> > > > \�[Y]\���[\�H ��\\�X��cks'?
> > > > >
> > > > Y�]   ����X[�H�Ü(tm)��^Z[�X\�Hjust point to a
> manual or
> > > > �Y����]��[Y[��@s.
> > > > >
> > > >
> B��������&�v����W76vR�����У�ɽ��%
>  4 Mainframe Discussion List
> > > > ><[email protected] On Behalf Of Michael Oujesky
> > > > >Sent: Tuesday, June 30, 2026 10:28 AM
> > > > >To: [email protected]
> > > > >Subject: Re: Net bytes per track
> > >�B���B���4�26��&W0sed data set.
> > > > B��֭6�V��4(��4(�At 10:13 AM 6/30/2026, Michael
> Watkins wrote:
> > >��IÛs]K�        �Ñ-T�MS compressed files super-block and
> write full
> > > > ��X�ks of
> > > > data'�]�[H\KX��\��X�H��Y�[�H�[�ard
> > >������X��\��Y]��[�\�H   Ù
> [�X���\\�X�locks'? Please explain.
> > > > > B���������&�v����W76pe-----
> > >�����N�P�HXZ[���[YH\��\��[Û^\�P�KSPR@N@
> > >LISTSERV.UA.EDUÛfB���&V��b�bÖ­6�V��V�W6���>
> > >�[��Y\�^K�[�HÌOE��N�
> > >�SCB���F�$ï¿½ï¿½Ô [email protected]
> > > > > �X��XÝ^�N��]�]\�\��X��
> > > > >
> > >
> > >B�����9�Р�եÑ"����É*��M5L����
> > >I��Í*����les super-block and write full
> ���X���Ù^]K���SIZE becomes logical (i.e. the buffer size
> of ��]Hused between the applcation and the SAM access method.
> > >  > >
> > > > ��YH�Q�M�T�[�HM�MH�Q��X�Ü(tm)�Ü^H@ctual
> > > > physical size �Û^H�XÚ>B�����5�� ael
> >
> >��B���B����b�#��##b�֭6�V�vF���2prote:
> > > > > ï¿½ï¿½Û [�U�[�Ù(tm)\�Q[���[�Î^�\�M�Y\�
> > >M��� bytes per track on a
> > >��33��'WBF�RÖ?��VҢ��2BLKSIZE is 32,760 bytes and
> > >only one ��&��6�v���`it on a track.
> > > > > �B����F�Ö?�Ö-�RF�R��V�B�` data on a
> > > > > track, half-track blocking is
> > > > ��\X�[y used. There is a 668-byte inter-record gap on a native
> > > > > ���L
> > >]\��Û^H�[�JK�X�\È(tm)Y[��\icated on RAIDed
> > > > ����H]�X�\�[�[�\��T�\��@tecture. This
> > > > means there is a
> > >��Ö?��VÒ?�b�G&6� BLKSIZE of 27998 bytes since
> 668+(2x27998)=56664.
> > > > >  >
> > > > > ��Ü^H]H�]�]X�]H�X�Ü(tm)�\�YX[�s half-track
> > >��&��6���r�V�2#s�#�'�FR$ĵ4��Rsince 349 x
> > >80 = 27920 and
> > > > > �\�H\Û?Ý>��H[�B� > >
> > > ��NN�Ü^H�LX�]H�X�Ü(tm)�B������ >Also
> > >keep in  mind that z/OS will append 32 bytes onto each block
> > >��v�V�E4�E�S�U�DT�DTB�27V6�f�VB��Vning less
> > >space for data ��&V6�&G2�2f��&���  > > B���4( >
> > >> B��ⴴ���=ɥ������5��Í...�����--
> > > > > ����N�P�HXZ[���[YH\��\��[Û^\�P�KSPRS
> > > > > �LISTSERV.UA.EDU> On
> > > > ���Z[�Ù^���\�ZX�X[�B��>
> > > ��[��[Û(tm)^K�[�H�K����HCB����F�$�ï¿
> > > ½[email protected]
> > > > > ��X��XÝ^�N��]�]\�\�rack
> > > > ��B����4UD���F��2V֭��&�v��FVBg&�ï
> > > > ¿½ outside of the Texas
> > >��6��G&���W"w2V֭�7�7FV��
> > >��D���B6Æ­6�ƭ�2�"�V�GF6��V�G2V��W72�ï¿
> > >½u expect them
> > > > �����HH�[�\�[�Û>��Hï¿½Û [�t is safe.
> > > > ��B���ä'¶VW��6VV��rg&�Ò'Sb�64 bytes per tack
> > > > for 3390 pack how
> > > > > �\�]]\�mined
> > > > > �B�������)���I�������4(�ï¿
> > > > > ½ >
> > > > > �Û^[Û<�[��K���]�N0�UT���H][H���\�\
> > > > > �i <
> > >��V#ffVS�&#r�F�&2�&WVW7DÆ-7G6W'b�V�V@u> wrote:
> > >��� ��� > The net bytes (i.e. longest record you can write
> > >to that
> > > > > ���X��H�\�Y\Èz@ access method as there is overhead
> (control bytes).
> > > >  > > ���S�\È>ÝsYY���\]HH\��\Ý(tm)X�Ü(tm)which
> > > > can
> > >���f�B��G&6��W6��rU�5��6VP�>
> >
> >�Î<��\�Y�[��K���KÝOE���Ú<����ËsX�K���K�����en/zos/3.2.0?
> > > > ��Â'���4(�� > > Unless you are using EXCP the hardware
> > > > track capacity is �� irrelevant,
> > >����9�9��9�8���9��9��9���&֭�RFï¿
> > >½R0tual bytes per track (and
> > > > ��f&�W2'�$ĵ4��R���
> > > > > ��B����=��QÕ"��)ո��0ï¿½ï¿½Ø ï¿½ÐEUR�(ï¿
> > > > > ½×?UK�AM Joseph Reichman <
> > >���S�#cCVC62�F�&2� [email protected]> wrote:
> > >������� Would anyone know how to get the net bytes per
> > >track for a
> > > > > ��33�����
> > >
> > >----------------------------------------------------------------------
> > >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
> > >
> > >----------------------------------------------------------------------
> > >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
> >
> > ----------------------------------------------------------------------
> > 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
>
>
>
> --
> Mike A Schwab, Springfield IL USA
> Where do Forest Rangers go to get away from it all?
>
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> send email to [email protected] with the message: INFO IBM-MAIN
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