DOS: the precursor of all modern operating systems
It’s amazing that even though the final official version of DOS was released in the year 2000, DOS can still be found quietly working away behind business critical applications in companies and public sector organisations. Read on to find out how Cloudhouse can help you with migration and customisation.
What is DOS?
DOS stands for Disk Operating System. Version 1.0 of PC-DOS was released with the first PC back in August 1981. It revolutionised computing. DOS is the precursor of all modern Windows operating systems: it’s a single tasking, single user, non-graphical operating system.
Companies created many applications in DOS running important internal processes.
Between 1981 and 1995, all DOS applications were 16-bit: designed to run on 16-bit microprocessors. Some of the popular frameworks from this era include Turbo C/C++, dBase, QuickBasic, Symantec Q&A and Microsoft Visual Basic 1, 2 and 3 to name just a few.
These days, with 64-bit CPUs being the norm in the mainstream personal computer market, this causes issues for old DOS software. The 16-bit CPU instructions required to run 16-bit applications are not accessible from 64-bit Windows. In fact some 16-bit applications fail to run even on 32-bit versions of Windows.
Companies who still rely on DOS applications are faced with difficult choices when it comes to upgrading their systems.
In most cases with commercial-of-the-shelf (COTS) solutions, these will no longer have vendor support, and in many cases the vendor may no longer exist, meaning there are no straightforward upgrade paths for organisations to take.
On top of this, the in-house developed applications from this era are often highly complex, and very difficult to re-factor into modern frameworks – and that’s even when you have the source code. If the source code is lost, it’s even more difficult.
Here at Cloudhouse we have also found that many applications of this era used ingenious hacks and undocumented APIs to achieve results – but these can cause unexpected problems or reliability issues when using existing publicly available solutions.
Cloudhouse can help: our team has MS DOS experience, and we can support you with migration and customisation. This knowledge can be hard to come by these days, but we have worked successfully with clients who have tried and failed to update their system before.
Symantec Q&A Database
We successfully migrated a Symantec Q&A Database system with hundreds of complex batch files and macros to run on Windows 10 x64 / Server 2016. Our approach meant the existing batch files and macros could generally be used “as is” without modification. We also optimised a 16-bit CPU emulation layer to get the required performance on the client’s hardware.
We worked with a company using an MS-DOS application for interfacing with 1980s telecommunications billing hardware over a serial port. This was successfully migrated to work with Windows 10 x64 and now uses a USB serial port.
Cloudhouse is experienced in many development environments
Cloudhouse has experience in MS-DOS software development, and development environments replicating a range of tools from this era including (but not limited to)
- Microsoft Macro Assembler (MASM)
- Turbo C / C++
- Turbo Pascal
- Symantec Q&A
- Novell bTrieve
- Microsoft Access 1 & 2
- Visual Basic 1, 2 & 3
Software diagnostic tools
In addition we have experience using the software diagnostic tools of the era such as
- NuMEGA SoftICE
- Windows CodeBack
Want to find out more?
If you would like to find out more, contact us for a no obligation conversation. We also offer a 100% Promise to all new clients who purchase a license agreement with us: you will be able to run your legacy app on the latest version of Windows or your money back.