The origins of AppSense

A long time ago (1998) in a city far, far away (London and I live in West Yorkshire some 200 miles north), I was a consultant working as part of a team implementing a new Citrix environment for a private bank. I think it was probably MetaFrame 1.0 on NT 4.0 Terminal Server Edition but I may be wrong – I started with WinFrame 1.5 in 1995, albeit with an OEM version called NTrigue from Insignia Solutions, based in High Wycombe, who Citrix went on to acquire (and with it Keith Turnbull and Jon Rolls) . All was going well until I noticed that one particular user had somewhere approaching fifty executable files in their home drive and was periodically running them on our shiny new (physical) servers. Back then, there wasn’t anything like AppSense Performance Manager, as AppSense hadn’t yet come into existence, four physical processors was about the most you could put in a server (and that was very expensive) and a few gigabytes of RAM cost more than the server itself so resources were at a premium and needed protecting. We therefore had a problem in that line of business applications were competing with all manner of “fun” software – probably what might be classed as malware these days.

My background is in software development – six years as a UNIX developer after graduation in 1988 and I wrote my first programs, initially in BASIC and then 6502 assembly language, in 1980 on a Commodore Pet – so I set about developing something that would stop this user from running any of these applications in order to preserve server resources.

So EStopper from ESoft was born, baring in mind that the two most difficult challenges in software development are not actualy writing the code itself but what to call a product and what icon to use.

The very first version used Image File Execution Options (IFEO) in the registry coupled with File Type Associations (FTAs) so was very much a blacklisting approach. You will have probably used the admin interface for this at some point – it was called “regedit” (my career started out in the non-GUI days so I couldn’t, and still can’t, code GUIs). All of the development for version 1.x was done out of hours, as I had a regular day job as a consultant, so was in hotel rooms, trains and late at night at home after my wife had gone to bed. For version 2.0 I was allocated a whole month where I had to learn how to write GUIs which cured me of ever wanting to be a full time developer again!

From here came the idea of Trusted Ownership, which obviates the needs for whitelisting or blacklisting thus simplifying deployment so an out of the box/default configuration can give instant protection from all external executable threats. I’m  not sure how I came up with this idea but by this point the first full-time developer had been recruited, as we’d sold the product to a couple of our “tame” Citrix accounts (as an “independent” organisation called iNTERNATA),  and whilst he was a fantastic coder, he did his best work in the early hours of the morning so I’d get phone calls around 3am asking about some aspect of Windows NT security – and I needed my beauty sleep even back then!


Auditing of who was denied access to what was in the product from the very beginning but after seeing a denial of something called “porn.exe” in the event logs, I thought that a feature to take a copy of denied executables, purely for research/disciplinary purposes of course, was a good idea. And, no, I never did investigate “porn.exe” (yes, really) although archiving is still a very useful feature today to use when understanding a new environment so denied content can be examined without having to recreate it.

So finally AppSense the company was born in 1999, with dedicated sales and development resources and the EStopper product was rebranded to be called AppSense as that was the only product they originally had. Even when Performance Manager joined the stable a few years later, the installer for what eventually was rebranded to Application Manager was still called AppSense.msi for a while.

And the rest, as they say, is history although the origins of Environment Manager are also “Quite Interesting” which I’ll leave to another time.


Author: guyrleech

I wrote my first (Basic) program in 1980, was a Unix developer after graduation from Manchester University and then became a consultant, initially with Citrix WinFrame, in 1995 and later into Terminal Server/Services and more recently virtualisation, being awarded the VMware vExpert status in 2009 and 2010. I have also had various stints in Technical Pre-Sales, Support and R&D. I work as an independent consultant, scripter and trainer, live in West Yorkshire, England; have a wife, three children and three dogs and am a keen competitive runner when not injured.

One thought on “The origins of AppSense”

  1. I’ll wager a small bet it was Citrix Picasso in that bank and I also recall the first AppSense product being called APPSENSE 🙂 AppSense APPSENSE if I am not mistaken. Great pioneering times – the look on people’s faces when Performance Manager delivered on its demo 🙂

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