• Please review our updated Terms and Rules here

DOS Debugger?

U

uriahsky

Member
Joined
Jan 23, 2012
Messages
37
Relax, I am not doing anything evil. I own the hardware and I own the software dongle which does not work anymore. I even found one of the original programmers who recompiled some of the programs to run without the dongle but there were a few that he didn't have the source code for. The company is long gone, you can barely find a trace of them on the internet.

I need a DOS debugger/Disassembler??? so that I can either figure out how the dongle worked so I can bypass it or to compare files between the ones that were recompiled to not use the dongle and the ones that require the dongle so I can learn from the changes that were made.

I am having a hard time finding one that will work in Vista that can handle DOS .exe files. MS-Debug only does .com files and most others I run across don't seem to do DOS programs but I know very little about this stuff.

What type of program should I be looking for and does anyone know of any free versions?

Thanks again,
Russ
 
At least for the dis-assembler part, you can't get much better than Sourcer. I've heard IDA works well too. Both are commercial.
 
IDA is an amazing disassembler. It's windows based, so should work in vista, and it'll chew on any .exe file you give it.

The dongle software itself is DOS based though? soft-ice (s-ice.exe) is an amazing TSR debugger that I have used to crack many DOS programs with. You can set it up to monitor the LPT ports on your computer and pop up whenever they are accessed, and that would give you the locations in the code where the checks are. you could probably then take that info back to IDA for examination. You'll still need to know x86 assembly to really understand what's going on though.
 
Ollydbg is one of the better free debuggers, not sure what all it supports though as I don't use it regularly. All the others mentioned are good but cost money. Only other thing you could do is use something like hiew (Hackers View) which is an old hex editing favorite with disassembler included but that would be best run in dos, not sure about Vista.
 
I use IDA as well. It not only handles x86, but quite a number of other processors as well. It's one of the best I've seen.

There is a free downlevel version of IDA here. It'll do what you need.
 
Not everything that starts under dos runs in real mode...If your programs use some kind of dos extender then different tools should be used. It might be useful to know the dongle's brand and probably the software that you're dealing with.
 
Thank you, a lot of good suggestions. I will look into each of them. I don't think Ollydbg works with DOS programs but I could be wrong. I tried it a while ago and couldn't seem to open any of my files.

The dongle is a SSI Activator, in case anyone knows anything about it. it has a custom chip that you can't find any info on it. I contacted a number of people who said the could crack it but most contacts never panned out. There are about 15 .exe files that access the dongle and some people wanted 300.00 to make a patch, but when I told them I needed fifteen programs patched they didn't think they could do it. The programs are DOS based program to run a circuit board tester. I don't know enough about them to know if they use real mode or not. I know very little about this so any guidance would be appreciated.
Thank you
 
Ask these questions the programmer that recompiled for you the sources without the dongle code. Also ask him to give you the source code part that accesses the dongle. Ask him for documentation that they used for dongle and possibly for the dongle's SDK.
 
Also - if you have the executable files for the ones he fixed - before and after - would be interesting to do a comparison.
 
I've got an OEM kit for one of the printer port dongles--I think it's Aladdin. The code supplied is complied--you don't get source code. You get lots of variants for various language environments and instructions on how to use it, but source code for the dongle access isn't supplied.

Most dongles tend to be something fairly simple--usually a CPLD that "scrambles bits" or performs as an LFSR or some such thing. You could, I suppose deduce what's in a dongle using a logic analyzer, but it's simpler to look for the (usually the same) dongle code in each file and patch it appropriately.

If you could find an old copy of SoftICE for DOS, that would make the job a lot simpler, as you could set a breakpoint to interrupt when the printer port is being accessed. I wonder if you could use Mike's 8086 emulator to accomplish the same thing...
 
Last edited:
george said:
Ask these questions the programmer that recompiled for you the sources without the dongle code. Also ask him to give you the source code part that accesses the dongle. Ask him for documentation that they used for dongle and possibly for the dongle's SDK.
Click to expand...

I am going to ask him for some help once I get clear on what works and what doesn't but, I really appreciate Paul's help and I want to make this easy on him. He still works full time and I don't want to abuse his kindness. So I am going to try and do as much as I can and then see what he can help with. He told me he doesn't have everything and he had to dig through his garage to find what he sent me so he may not some files.
Russ
 
westveld said:
Can you post pics of the circuit board tester?
Sounds interesting!
Click to expand...
UTI Protec System 1.jpg
I have wanted a tester like this for years. I have tons of test gear but this is one thing I never could afford. It is a bench top tester that does In-circuit Functional Testing of IC's. It was made twenty years ago and this method fell out of favor for numerous reasons. There are still a few companies that make them. ABI Electronics, Qmax, Diagnosys, Polar. But they start around 20K and upto 100K or more. These are made for repair people. They are like mini versions of the big testers made by Agilent, Checksum, and Teradyne, that are used in manufacturing to test pcbs at the end of the line. Over the years I was always hoping someone one would make a cheaper DIY version of this type of tester but I haven't seen one yet.

It does things like: Test IC's in-circuit, Checks for opens, shorts, runs truth tables on the IC's, back drives to create isolation. Creates Schematics, Runs V/I tests, (Huntron) and a number of other things. You can create your own tests for IC's not in the library. It also has an automatic test generator for IC's. You can view logic diagrams during testing. The one I have is a 48 Pin tester but this can go as high as 128 pin. It uses clips to clip onto the IC. I attached a pic of the front of the unit. Even though it is twenty years old it does most of what the current testers do. Every repair bench should have one of these.
Russ
 
I find it amazing that software, which is really only useful when you have one of these test machines, needs a dongle in order to verify that you're an authorized user. It's practices like that which make me want to crack the software just out of principle.
 
I have two pieces of software that I use for business, and they both require use of a dongle.
I alternate between a desktop in the office, and a laptop to take to meetings, and I would often forget to take the dongles with me.
I contacted: http://www.software-key.org/
They made a dongle emulator for me, so that I no longer need the dongle in either computer.
Makes life much easier, and I'm not doing anything illegal.
I've got the software and the dongles - I just don't have to use the dongles.
It wasn't cheap ($ 300), but it may be easier and save a bunch of time/effort (which itself is worth something).
 
You must log in or register to reply here.
Back
Top