DiskLock, From Fifth Generation Systems, and later from Symantec as Norton DiskLock, is a data security tool that can lock a hard disk or individual files or directories so that it requires a password to access any data. It can also log activity to detect unauthorized access attempts. It also features the ability to lock the system after an idle usage period. There were versions for PC and Mac.

DiskTop is a desk accessory intended for MacOS 6 that lets you perform file management and search files without having to exit the program you are running. In MacOS prior to version 7, you could only use one application at a time. You would have to exit your application in order to return to the Finder desktop. However Desk Accessories are always available to all running programs, so DiskTop works around this limitation by making file management part of a Desk Accessory.

First released in 1989, DoubleDisk was the first real-time drive compression product for DOS. It is a fairly no-frills program and sticks to what it does best. It was relatively low cost compared to its later competitors. and Expandz! Plus

DoubleDOS is a simple and easy to use multitasking tool for DOS. It can preemptively run up to two DOS programs at a time. Its main advantage is that it requires very little RAM overhead compared to other multitasking or task switching environments. Because DOS programs can and usually do bypass OS calls, many programs must be "patched" in order to work. things at once, then this would have been a good choice. Reportedly, the first version may have worked with DOS 1.x.

DoubleTools is a set of Windows-based utilities that adds functionality to DoubleSpace, included with MS-DOS 6.0.

Dr Solomon's Antivirus was a top rated commercial virus scanning suite. There were versions for DOS, Windows 3.1, 95, 98, Novell, SCO Unix, Solaris, and OS/2.

Dragnet, from Access Softek, is an advanced but easy to use file search utility that features the use of GUI input, Boolean operators, synonyms, pattern file definitions, multitasking, and the ability to search across multiple files. The original version is designed for Windows 1.x.

DS Backup Plus is a simple hard disk backup utility. It was not as full featured or robust as other backup products, but it got the job done. Backups can be done from within the program or from the command line. It supports wildcards, filespec inclusion/exclusion, backup to any DOS drive type, automatic disk formatting, incremental backups, and claims to be faster than DOS backup and restore.

DS Manager is a menu and file management shell for DOS. It features password protection with the ability to display different menus for different users.

DS OPTIMIZE is a disk defragmenter tool. It has a few more options than its competitors, and has a "fast" mode that does not protect against interruptions. This tool competed against Mace Utilities, The Norton Utilities, PC Tools, and many smaller defragmenter tools.

DS Recover, from Design Software, is a set of file utilities for DOS that lets you unerase files and directories, and unformat disks. It competed against the Norton Utilities, PC Tools, and Mace Utilities.

Easy Access Menu system, from TengWare, is a customizable menuing system for DOS that features a built in calendar. It is shareware, but there are few archived versions of it out there.

Spinnaker Easy Working DOS Manager is a menu system and file manager for DOS. It was bundled with a number of computer systems including Packard Bell. use of a mouse. It features a customizable application menu, primitive file management, and menu options for the disk utilities commonly included with DOS. It includes built in help, and a tutorial.

EasyDesktop, from MicroSeconds International, is an alternative desktop shell for Microsoft Windows that uses a more compact text-based file list and integrates its own file manager.

Executive Card Manager, from Hewlett-Packard, is a Rolodex-like database for storing contact information. It features the ability to transfer information between other common applications. screen.

HOT, from Executive Systems - the makers of XTREE, is a highly configurable menu shell for the IBM PC, with built-in "hot menus" for common DOS functions. It features a pop-up file browser, a small text editor, the ability to feed keystrokes to applications, and automatically sets up known programs found on your hard drive.

Expanz! is a drive compression system consisting of an expansion co-processor card and a set of software. It competed against Stacker, DoubleDisk and SuperStor. However Expandz! never made a software-only system. It worked a little differently as it compressed an entire partition rather than using an uncompressed host partition. While a hardware co-processor was useful for slower computer, software based solutions were able to surpass its performance with newer, faster CPUs.

Expert Calendar is a simple, easy to use, scheduling database application for MS-DOS. It features the ability to search by name or subject. It includes a pop-up calendar. It can print calendars, planners, and agendas, and it supports dot matrix and laser printers.

Expert Fax Forms is a set of stylish fax image templates for use with PC based fax programs or fax machines. It includes a set of image templates in PCX format, and a basic graphics editing program. Supports CGA, EGA, and Hercules graphics and the use of a mouse.

Expert Utilities is a rudimentary file manager shell for DOS. It provides an on screen directory listing and a visual command menu. It does not use the mouse.

EZ-DOS-IT was a very low-cost low-resource multitasking program for DOS on the IBM PC and compatibles. It claimed compatibility with most popular software of the time. However, the initial 1.0 release had serious bugs, was copy protected, and was not compatible enough for many people. Although these issues were quickly fixed and copy protection removed, it earned them bad reviews.

EZ-Drive is a hard disk partitioning tool bundled with new hard drives. It detects, partitions, formats drives, and installs BIOS overlays, all in one easy to use program. Such setup programs were often necessary due to the complexity of BIOS size limitation and the skyrocketing size of new hard drives. EZ-Drive is similar to Ontrack Disk Manager.

EZ-Tape backup system for Windows and DOS.

Failsafe Computer Guardian is a DOS TSR utility that prevents programs or other users from accessing or making changes to designated files on the hard drive. It includes password control, user groups, logging, keyboard locking, screen blanking, and support for Microsoft windows. Notably, it can do all of this with minimal DOS memory overhead, only 14k of RAM.

Fastback, by Fifth Generation Systems, Inc, is a backup utility for DOS. Its key feature is that it can read and write both a floppy disk and hard disk at the same time by making use of dual-channel DMA. Combined with speedy data compression, it can make a very fast backup.