Commit CUBE Library version 13 of February 1972.

1. Commit library tape images, directories, and extracted text files.
2. Commit additional utilities under Unisys-Emode-Tools.

CUBE-Library-13/CAST-Examples/README.txt

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+CAST Tape Examples for CUBE Library Version 13.
+
+The CUBE_LBR tape image in the library is in CAST format, a sequential
+source archive originating from the days of the B5000. The B5000 did not
+have the large Head-per-Track disks that were introduced with the B5500,
+only two relatively small drums, so source programs had to be maintained
+either as card decks or on tape.
+
+The CAST format allowed multiple source modules to be maintained on a
+single tape volume. These tapes were maintained by the standard utility
+program MAKCAST/DISK. The Algol and COBOL compilers understood this
+format and could compile programs and include individual routines
+directly from CAST tapes or a disk file.
+
+CAST tapes had a directory on the front of the tape that identified the
+files stored on that tape. The directory included the relative record
+number of the start of each file. This allowed MAKCAST and the compilers
+to use the Algol SPACE statement to position the tape to individual
+files relatively efficiently. If the CAST file was on disk, SPACE
+provided random access to the modules. If the file was on tape, it could
+take about five minutes to traverse a full reel.
+
+Here is what I have deduced about the format of CAST tapes:
+
+    1. The tape is labeled with standard B5500 tape labels.
+
+    2. Tapes are written with fixed-length 448-character (56 word)
+    blocks.
+
+    3. The first three blocks on the tape contain a directory of the
+    files on the tape:
+
+        a. The first word of the first directory block appears to be a
+        count of the number of blocks in the directory. This appears to
+        be a fixed value of 3, however, and is hard-wired into the
+        MAKCAST/DISK utility program that maintains these tapes.
+
+        b. Entries in the tape directory are variable length,
+        consisting of N+4 characters, where N is the number of
+        characters in the library module name.
+
+        c. The first character in an entry is the length in binary of
+        the module name, followed by the characters of the name.
+
+        d. Following the name are three characters that specify a big-
+        endian 18-bit binary number -- the 1-relative logical record
+        number on the tape where the module starts. This number is
+        relative to the first non-directory block on the tape (i.e., the
+        block following the directory blocks).
+
+        e. Directory entries are not split across tape blocks. If there
+        is insufficient room at the end of a block for the next entry, a
+        zero-length entry is inserted at the end of that block and the
+        entry is stored at the beginning of the next block.
+
+    4. The remainder of the tape after the directory blocks consists of
+    blocks with the text of the library modules.
+
+    5. The first word of each of these text blocks is the binary value
+    of the 1-relative record number of the first logical record in the
+    block, using the same relative basis as in the 18-bit directory
+    record numbers.
+
+    6. The remainder of the block consists of five logical records of 88
+    characters (11 words) each (thus 5*88+8=448). The first 80
+    characters of a logical record hold a card image. The last eight
+    characters of a logical record do not appear to be used and are
+    zero.
+
+    7. The library is terminated by a physical tape mark and ending tape
+    label.
+
+    8. A 2400-foot reel of tape could hold almost 110,000 records at 800
+    bpi. The maximum capacity of a library is limited by the three
+    directory blocks and the 18-bit record number in the directory
+    entries.
+
+The MAKCAST/DISK program is described on page 5-5ff in:
+
+    http://bitsavers.org/pdf/burroughs/B5000_5500_5700/
+    1024916_B5500_B5700_OperMan_Sep68.pdf
+
+The Algol and COBOL compilers use "$$" cards to include source modules
+from a CAST tape or disk file into the program being compiled. These
+cards are described on page 4-41ff in the link above.
+
+
+CASTTST.card
+    Card deck illustrating how to compile a program from a CAST file. By
+    default, the "A" file was "CASTA/LIBRARY" on disk.
+
+COMCAST.card
+    Card deck illustrating how to compile and run a program by inserting
+    fragments of a module from a CAST tape and insert patches between
+    the fragments. By default, the "C" file was labeled "CASTC" on tape.
+
+CPYCAST.card
+    Card deck for a program to copy the "CASTC" file from tape to
+    "CASTA/LIBRARY" on disk
+
+MAKCAST.card
+    Card deck to illustrate simple use of MAKCAST/DISK. This deck
+    generates a listing of the tape directory, a listing of module
+    URS046, and punches a deck for module PTS024.
+
+PTS051.lst
+    The listing resulting from the compilation and execution in
+    COMCAST.card.
+
+__________
+2018-05-27 Paul Kimpel
+    Initial version.
+
+