File Manager
A tool for browsing and editing data files field by field, using a copybook to show each record in a readable layout.
Also written IBM File Manager, File-AID, formatted browse, data editor
Record data on the mainframe is hard to read in a normal editor. Packed decimal and binary fields look like nonsense, and nothing tells you where one field ends and the next starts. Tools such as IBM File Manager and File-AID solve this.
They read a copybook that describes the record and use it to show the data formatted: one field per column, with its name, and numbers shown as numbers. You can browse or edit a sequential dataset or VSAM file this way, change one field in one record safely, and search by field value, such as all accounts with a negative balance.
They also do many other data jobs: comparing two files field by field, copying records that match a condition, creating test data, and printing records in a readable form. Most of these can also run in batch.
Because they make it easy to change data, sites control their use on production files carefully. In test, they are one of the most useful tools a developer has.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
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- CopybookA shared block of COBOL declarations kept in a library and included into programs, so a record layout is defined once.
- VSAMA family of dataset types built for fast record access by key, used where applications need to look records up rather than read them in order.
- Packed decimalA compact way of storing numbers, two digits per byte, used heavily for amounts in business records.
- DatasetWhat a mainframe calls a file: a named collection of records with a defined structure, rather than a loose stream of bytes.
- ISPF editorThe full-screen text editor used to write and change JCL, COBOL, REXX and anything else held in a dataset.