Design Simulation Systems Ltd
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Who are we - and what about cybersecurity?
Design Simulation Systems Pty Ltd is an Australian company, which was originally born in Singapore, with the aim of developing most of the stuff described in these pages, until it was bought by the National Computer Board. It is now a consultancy, largely devoted to development work centred around Unix based security applications, and custom simulation model creation, in an environment of Sun servers.
Our interest in security has been fostered by the fact that this site has been under attack by parasites trying to implant viruses since 2009, and by a botnet since Christmas Eve 2012.
To counter this nuisance, we searched the market for a suitable defence and, finding none, we designed our own IDS/IPS, which has successfully defeated every single hack attempt and, by reporting the IP addresses to their ISP's, has helped to remove 67346 of these parasites from the internet - and counting...
If you're interested in the kinds of hack attempts we've withstood over the last five years, there's a set of files containing anything from 4,000 to 10,000 hack queries, ranging from SQL injection, to dumb PHP and WordPress hacks, to attempted bash exploits, and a bar chart which is updated daily, showing how many parasites are banging their heads against our firewall this month
If you're interested in trying the IPS, to protect your website, drop me a line.
We have also written reams of security software - including the Forticode Enterprise System, and Forticode Authentication Engine - for SteelPlatez Security, Forticom, and Forticode Security.
For our own protection, we use the Forticode Enterprise system to authenticate users of our download page. There's a description of it here and a PDF user's manual here. For those needing more information, there's also a PDF administrator's manual.
If you already have an account on our Forticode system, you can access all of our download freebies by logging in here
If not, create an account here.
More recently, we developed an Encryption Key Management system, for protecting encrypted data-at-rest, in a database or flat files. This key management trick ensures that nobody - not even root or a DBA - can access or compromise the encryption keys used by a system to encrypt sensitive data - and you don't need to hide the keys in a concrete bunker...
The Simulation Stuff
In an era where an electronic circuit is a slab of silicon, designed by writing a language like VeriLog or VHDL, with virtually no need to understand the mathematics of circuit design, or the physics of semiconductor devices, we present a set of tools from a more gracious age. From an age when computers were still drawn by horses, and it took an engineer to design something. Not a software package.
Not content with offering this anachronism, we compound the injury by also describing a digital circuit simulator, which simulates digital logic at the device level, not the gate level.
I guess this is all precipitated by the fear that, one day, there will be nobody left who actually understands how or why stuff like VHDL works, and colleges will have stopped teaching mathematics, because it's all too hard, and too many people fail the courses - which isn't politically correct, because it damages their delicate egos....
Totally unrelated to analog simulation is a pot-pourri of Unix articles, with a leaning towards database applications. If you're not that good a programmer, they'll either help, or put you off, for good... (Click on 'Real Programmers', above, to see if you qualify).
So, what are these analog tools? I hear you ask...
First, you might like to see a complete electronic circuit design cycle, starting with schematic capture, proceeding to a time-domain simulation, and finishing with some DSP post-processing of the result, to produce a Fast Fourier Transform of the output waveform
GEX - a graphical schematic entry and editing tool
GSP - a high-speed schematic to SPICE netlist compiler
Graphical circuit stimulus editor
Vspice3 - a graphical simulator interface
Vspice3 Mathematical waveform manipulation tools
Vspice3 Digital Signal Processing waveform manipulation software
Laplace transfer function components for high level system simulation
SPICE2 simulation engine
SPICE3 simulation engine
Vmodel - A semiconductor device modelling tool
Vmodel2 - Data sheet to SPICE parameter extraction and curve-fitting tool
Comprehensive set of common semiconductor and mechanical component libraries
Reverse-engineering tool from SPICE netlist to GEX schematic drawing
Full Documentation in PostScript and Unix man page format
These tools are all available for free download, compiled for either Linux or Sun SPARC. No special gizmos, like Motif or Java are needed, and they'll run quite happily on anything with a working X11 library.
Among the downloads is a comprehensive set of component libraries, including a special library of Laplace-transform primitives, for behavioural high-level simulation. Additionally, there's a library of mechanical bits, like motors and gearboxes, for simulating servo systems and the like. Not to mention PCB tracks, op amps, SCR's etc.
Since even the most comprehensive library may miss the very device which you need to use, we also supply a set of component modelling tools
Vmodel will make a computer model from the characteristics supplied on the data sheet, while Vmodel2 accepts X-Y characteristic curve data, and accurately extracts and optimizes the relevant SPICE parameters by curve-fitting techniques
Far more interesting, is the fact that, when the simulation is finished, you can apply a whole heap of mathematical functions, including forward and inverse Fourier transforms, convolution and deconvolution functions and display results in the complex plane.
Nearly forgot: You can also download either the SPICE or Spice3 simulator (or boh), each of which has functionality that the other doesn't have.
Source code is available for an extortionate fee...
Can't make it work on your version of Linux?
Need to model an obscure semiconductor device?
Interested in discussing authentication systems or IDS/IPS?
visitors since January 1st