Browse Prior Art Database

Multi-Tasking File Manipulation Procedure

IP.com Disclosure Number: IPCOM000112309D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 97K

Publishing Venue

IBM

Related People

Anderson, B: AUTHOR [+3]

Abstract

Disclosed is a procedure for managing a series of sequentially named and ordered files. This name of this process is the Multi-tasking File Manipulation Procedure (MFMP).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Multi-Tasking File Manipulation Procedure

      Disclosed is a procedure for managing a series of sequentially
named and ordered files.  This name of this process is the
Multi-tasking File Manipulation Procedure (MFMP).

      In any multi-tasking operating system where a process utilizes
a series of sequentially named files, name selection conflicts and
file overlays can occur without strict controls.  This is very common
with error handling procedures running in a multi-tasking environment
that generate a series of dump data sets, one for each error handled
by the procedure.  There needs to be a way to control the sequence
number used to name the dump data set and a way for the error
handling routine to not reuse a sequence number already in use when a
dataset needs to be retained.  For example, a dump file naming
convention may be FILE001.DMP, FILE002.DMP, FILE003.DMP, ...
FILE032.DMP.  Usually a sequence number limit is set to manage system
resources.  If 32 is the maximum sequence number, once FILE032.DMP
has been reached the sequencing starts over at number one.
FILE001.DMP is written over with new data and the next sequence
number is 002.  If FILE001.DMP was held by another process, say a
dump formatting routine, then the file would be inaccessible to the
error handling routine.  In many operating systems, the file I/O
routines would cause the request to access the file to be queued and
the error handling routine would be in a wait state until FILE001.DMP
was released by the dump formatting routine.  To address this
problem, MFMP was developed.

      MFMP is a front end process that manages the distribution of
file names and provides single access to the data within the files it
names.  Management of file naming is performed through a table kept
in memory and in a checkpoint file which is kept across machine power
down.  This table, called the number control table (NCT), contains
information used to name the next file and current status of the
files (e.g., in use).  An illustration of an NCT which controls a
sequence of up to 10 files follows:

           Number Control Table

           --------------------

_____________________________________________

| Sequence | Date/Time |        | Alternate |

| Number   |  of Use   | Status | File Name |

|----------|-----------|--------|-----------|

|  0001    | 93140.1330|   1    | 17395032  |

|  0002    | 93140.1423|   0    |           |

|  0003    | 93141.0834|   0    |           |

|  0004    | 93143.1355|   0    |           |

|  0005    | 0000000000|   0    |           |

|  0006    | 0000000000|   0    |           |

|  0007    | 0000000000|   0    |           |

|  0008    | 0000000000|   0    |           |

|  0009    | 0000000000|   0    |           |

|  0010    | 0000000000...