GRABBER

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File Format
Name GRABBER
Ontology
Extension(s) .com, .exe
Released 1987

GRABBER is a screen capture utility for DOS, developed by Gerald (Jerry) A. Monroe.

Images are saved as self-displaying executable files. Older versions use COM format, and newer versions use EXE.

Contents

Discussion

Some of the registered versions have major version number 5 or 6 (or 4, apparently), though they aren't necessarily newer than the 3.x shareware versions. This is mentioned in, for example, the REGISTER.DOC file from the 3.98 distribution.

GRABBER may require a fairly accurate DOS implementation and PC emulator. The technical requirements differ by version of GRABBER, and are not well understood.

Some versions work in DOSBox-X, but others don't; though it might be possible to configure DOSBox-X such that they do. For best results, a full PC emulator such as 86Box, running actual MS-DOS, is suggested. Using only virtualization (e.g., VMware Player or VirtualBox) might not work as well as using an emulator.

Curiously, one of the sample files sometimes found with v2.10, INNARDS.COM, is an image of part of a hex dump of what looks like an older (lost or unreleased) version of GRABBER.COM. It contains the strings "GRABBER Ver. 2.0" and "Copyright (C) 1987 by Gerald A. Monroe". The sample files themselves appear to be identical or nearly identical to those that could be made by v2.10.

Version history

The file structure of the generated files evolved over time, so it would be nice to know the release order and dates. Unfortunately, GRABBER's version numbers are not in chronological order (except within a major version). And no version history documentation has been found. And few of the registered versions are available for analysis.

As a starting point, here's a list of versions, ordered by the copyright year embedded in the generated files.

Date Fmt Versions
(none) COM 2.10-2.20
1988 COM 3.0-3.2
1989 COM 3.2K-3.35 4.0-4.03
1990 EXE 3.50?-3.60 6.01-6.20
1991 EXE 3.70-3.93 5.50-5.52 6.30-6.32
1992 EXE 3.94 6.40-6.50
1993 EXE 3.96 5.60 6.60
1994 EXE 3.97
1995 EXE 3.98

Format details

The default save filename for v2.10 to v3.00 is "SCREEN_A.COM", "SCREEN_B.COM", etc. For v3.20 to 3.35, it's "SCREEN00.COM", "SCREEN01.COM", etc. For v3.60 to 3.96, it's "SCREEN00.EXE", "SCREEN01.EXE", etc. Later versions try to derive a name from the running program, or "MSDOS00.EXE"... if there isn't one, or "SCREEN00.EXE"... as a last resort.

Identification

[Information here might not be complete -- more research needed. Note that, for a given version, files using older (text, CGA) screen modes may be quite different from files using newer (EGA, VGA) screen modes.]

v2.10-2.20 (COM format): No readable signature. The first 16 bytes are 

fb be 81 00 8a 4c ff 30 ed 09 c9 74 20 56 fc ac

v3.0 to 3.30 (COM format): There's a string at offset 5 that's either 

All Code Copyright (C) 1988 Gerald A. Monroe

or 

All Code Copyright (C) 1988, 1989 Gerald A. Monroe

v3.34-3.35 (COM format): There's a string at offset 5 that starts with 

This file was created by GRABBER.COM Version

Early EXE format (~3.50): Verification needed. At offset 49 is the string 

All Code Copyright (C) 1987-1990 by G. A. Monroe

v3.60-3.98 EXE format: At offset 49 is the string 

Created by GRABBER

Software

The GRABBER distribution (at least v3.87+) includes utilities for converting to common formats such as GIF and PCX.

Sample files

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