Here's the Needle! Finding files fast with BACKDATA
From "VS Workshop",  Access to Wang, July 1990
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This month I'll demonstrate one way that you can use your backup listings as data for ad hoc inquiries, converting the print files into data files. The conversion process itself also provides an excellent forum for discussing Wang's COBGEN utility - a COBOL code generator perfect for simple programming problems such as this. So let's dive in!

Finding files in all those tapes

Picture a VS user who has just discovered that a file has be accidentally deleted. Backup tapes from the prior evening have already been sent off-site, and there will be a delay (and some cost) to bring them back. The prior night's backup tapes are on hand, but you're not sure whether the file has been modified between these backups - or even which days it was backed up. Our user settles with a groan before a large stack of backup listings and begins to sift through them.

My alternative to this scenario is to convert the listings themselves to data and store that data for inquiry purposes. With the data in this simple file format, sophisticated queries can be constructed with programs or the Wang File Management utilities (INQUIRY, REPORT) to find specific information fast. Instead of poring through reports - with the possibility of missing critical information - a search could be constructed using INQUIRY, REPORT, or other means.

Creating the BACKDATA file

Since print files are a form of consecutive file, they could be used by themselves as a basis for inquiry. I have used this technique in the past, retaining the print files as permanent logs and searching within DISPLAY and with text search tools such as FINDTEXT. The data file approach allows all file references to be combined into a single file, providing a full view of its backup and modification history.

In creating the backup data file (BACKDATA), you have a choice of the information you wish to pick up from the backup listing. Some fields may not be of interest and could be ignored, reducing the size of the output file. For my purposes, I chose to accept all of the fields and even add the date and time the backup was performed. The field locations in the input and output files are listed in Figure 1 (below).

The CREATE utility and an appropriate procedure may be used to convert the backup listings into BACKDATA format. If you use this approach, be sure to use the PAD option (PF2 from the INPUT screen) to move spaces into the record area before each print record is read. This is necessary because print file records vary in length and characters left in the buffer from prior records will be "carried" through to subsequent records, resulting in garbage in the output records.

Programming languages offer better control and more functionality than procedure-driven solutions. In my use, I extracted the run date and time from the second header record of the file and duplicated it as a time stamp within each record. I also appended the new listing information into an existing version of BACKDATA, checking for duplicate entries and removing entries over 60 days old.

The COBGEN utility

COBGEN is among the utilities that are supported by Wang Laboratories beginning with the 7.20 operating system. Like others, it was formerly a USERAID - distributed by the International Society of Wang Users but not maintained or supported in any way.

The purpose of COBGEN is to create a shell COBOL program with most standard sections of a COBOL program defined, allowing the programmer to concentrate on the real meat of the problem: the PROCEDURE DIVISION. It accepts information about the program from the user, then generates the code using standard names and sections. Other than main control paragraphs and file I/O, the PROCEDURE DIVISION is left for the user.

While not a requirement, COBGEN works best with CONTROL files for its file specifications. COBGEN can interpret these files, creating the required SELECT, FD, and file access sections. Standard PROCEDURE DIVISION file I/O statements are also generated.

Prior versions of COBGEN suffered from imperfect translations of CONTROL files, including mistakes when record areas were defined within more than one data element (i.e. redefined). The program checked that no COBOL reserved words were used for illegal purposes (such as data names), but the list of those words was out of date. Version 2.08.03 corrects most of these difficulties and adds some functionality as well.

The new version supports COBOL-85 as well as COBOL-74, and offers SORT operations using either the SORTLINK subroutine or the internal SORT verb. As before, code can be generated to handle FIGURATIVE-CONSTANTS, dates, calls to other programs, and the WORKING-STORAGE elements for calls to the GETPARM and PUTPARM subroutines. Up to nine disk files can be processed, and the workstation can display up to nine screens; a single print file is allowed. COBGEN relies on other Wang utilities (EZFORMAT for screens, CONTROL for file definitions, EZPRINT for report definitions) and optionally links to these utilities for convenience.

If you are conversant with COBOL, the COBGEN utility makes an excellent starting point for simple problems such as the BACKDATA conversion program. The CONTROL files created for use with INQUIRY and REPORT become the only input necessary to generate a shell program, leaving only the data field MOVEs and few other details to take care of. In short, COBGEN helps you to concentrate on solving the problem - rather than spending long hours chasing variable names and errors. Give COBGEN a try the next time you need to write a short program.

Figure 1: Field Locations for BACKDATA

Field description	Field name	Input Position	Output Position	Length
Location - Volume	VOLUME	3	1	6
Location - Library	LIBRARY	13	7	8
Location - File	FILE	24	15	8
File sequence	FSEQ	34	23	4
File organization	FORG	40	27	6
Record format	RECFM	48	33	1
Record length	LRECL	54	34	4
Number of Records	NRECS	59	38	7
Protection class	CLASS	70	45	1
Owner of record	USER	76	46	3
Creation date - month	CREMM	84	51	2
Creation date - day	CREDD	87	53	2
Creation date - year	CREYY	90	49	2
Expiration date - month	EXPMM	95	57	2
Expiration date - day	EXPDD	98	59	2
Expiration date - year	EXPYY	101	55	2
Modification date - month	MODMM	106	63	2
Modification date - day	MODDD	109	65	2
Modification date - year	MODYY	112	61	2
Error flag	ERROR	120	67	5
Backup date - year	TIMEYY	-	72	2
Backup date - month	TIMEMM	-	74	2
Backup date - day	TIMEDD	-	76	2
Backup time - hour	TIMEHOUR	-	78	2
Backup time - minute	TIMEMIN	-	80	2