Using MIT PC/IP with SLiRP & a virtual Cisco Router

In this video I’ll be covering the circa 1985 MIT PC/IP stack running on 86box trying to connect to a user mode network library, SLiRP. After that fails I’ll show how to break the stack apart so we can use WireShark to inspect the traffic, then how to replace the direct connection to SLiRP by using Dynamips to emulate a cisco 7200 router.

Caution it’s all command line!

I’ll cover adding a loop back adapter, installing WireShark, how to find the GUID’s of the interfaces, how to configure a HecNET bridge, and set it up to relay to a stand-alone version of SLiRP, then how to setup a virtual cisco router to do NAT, and also forward to SLiRP, along with taking network captures to show what is really going on!

Software used (in no particular order)

Or for those who prefer the written way…

what is going on?

In 86box, you have the ability to use the SLiRP library directly from the emulator. Which is all find and good, but sadly it gives you no visibility when things go wrong. And with MIT PC/IP things go wrong. Looking at the data through Wireshark sure would be nice, but how to we get it into there?

Well the simplest way is to just break it apart.

Broken apart into it’s components

Adding in a KM TEST loopback adapter to Windows now gives us a private network we can now attach programs to via the pcap API. Hecnet is a l2 bridge that can inspect and look for l3 traffic and then forward it via udp to another program. In this case I had made a version of SLiRP that will communicate via UDP, perfect for stuff like this!

One thing to keep in mind is that the ‘GUIDS’ of the network interfaces are unique to each system, the ethlist program will show you which is which. It’s also why renaming interfaces only helps you when dealing with old libpcap stuff!

Rename stuff so it makes sense! Otherwise, everything is Ethernet


Network devices:
  Number       NAME                                     (Description)
  0  \Device\NPF_{E7EB72FA-7850-4864-B721-2A3B38737214} (KM-TEST)
  1  \Device\NPF_{649448CA-969D-486E-AAC8-99F1993C701A} (Ethernet0)
Press Enter to continue...


With this information in hand, creating the bridge configuration is quite simple:

Loop \Device\NPF_{E7EB72FA-7850-4864-B721-2A3B38737214}


The bridge is for an uncompressed normal bridge connection between the KM TEST loopback interface and a UDP connection listening on port 5001 on localhost. Of note it’ll be forwarding TCP/IP related packets. Since we want the bridge to listen on UDP port 5000 we simply run it like this:

hecnet.exe 5000

Running the SLiRP redirector is just a simple matter of telling it which port to listen on, and where to forward traffic. In this case we’ll listen on port 5001 and forward traffic to 5000 on the localhost

slirp_rdr.exe 5001 5000

Thankfully, it’s that simple!

Running a ping fails (yet again) but this time we can see that they are doing ARP but for some reason PC/IP does not acknowledge the SLiRP library.

Just to verify, the HecnetNT bridge does see the source and destination address, and the SLiRP does indicate traffic in and out as expected.

Clearly the fault is on the PC/IP side, and most likely because it’s so old.

I then decided to build another network, this time using Dynamips to add in a virtual router.

Adding in a router

This complicates things as I’m not sure how to control the internal routing of the SLiRP library so the router has to NAT the PC/IP traffic to SLiRP, which in turn ‘NATs’ it to the internet. But rest assured double NAT (or even more) is quite common these days.

Configuring the router is somewhat straight forward, we are going to use pcap to listen on the KM TEST loopack, replacing the HecnetNT bridge. But it’s going to talk to the SLiRP redirector in the same manner:

set loopback=\Device\NPF_{E7EB72FA-7850-4864-B721-2A3B38737214}
set IOS=..\c7200-is-mz.19991126.bin
set NPE=npe-100
set RAM=64 -X

@attrib *.* -r
..\dynamips.exe -P 7200 %IOS%  ^
-m %RAM% ^
-t %NPE%  ^
-p 0:C7200-IO-FE ^
-p 1:PA-4E  ^
-s1:0:gen_eth:%loopback% ^

This creates a basic 7200 router with a 4 port ethernet card, with one port connected to the KM TEST loopback, and the other connected to the SLiRP library.

Configuration of the router is not very complicated either:

no ip domain-lookup
interface Ethernet1/0
 ip address
 no ip directed-broadcast
 ip nat inside
interface Ethernet1/1
 ip address
 no ip directed-broadcast
 ip nat outside
ip default-gateway
ip nat inside source list 1 interface Ethernet1/1 overload
ip classless
ip route
no ip http server
access-list 1 permit

This defines our default route for both the routing table, and the management engine to the SLiRP library, defines the NAT inside/outside interfaces along with specifying the ‘overload’ address will be the NAT’ing the PC/IP traffic behind the usual SLiRP user address.

Pinging the SLiRP gateway

This allows us to ping SLiRP, and get the expected response.

Working ARP/ICMP with cisco router

Checking the capture, we can see that yes ARP is working as expected, and the ping works without any issues.

On the router we can see the NAT translation.

Router#show ip nat translations
Pro Inside global      Inside local       Outside local      Outside global

And we can also check the SLiRP redirector for information on the current session.

SLiRP redirector started!
Press 's' for SLiRP stats
Press 'e' to exit.

Sent:           Recv:
stats!          4859

Proto[state]     Sock     Local Address, Port  Remote Address, Port RecvQ SendQ
tcp[ESTABLISHED]  632  4376    23     0   600
tcp[REDIRECT]     616    23 42323     0     0

Plus, we also have the Wireshark capture going showing the start of the TCP conversation

TCP connected!
Connected to VERT

So now we’ve connected to the internet and by breaking the process appart we can now inspect what is going on, and made modifications like adding a cisco router.

I figured that this may be something that other people may be interested in, as you can build far more complex virtual networks this way!

So, I finally sat down and beat Space Quest II

Finally beat Space Quest II!

No, really, I never played it all the way through. I thought it was also a good test of SarienPM, on Microsoft OS/2 2.0 Pre-Release 2, and much to my surprise despite having screwed up the sound code so that it’s always on, and not using an input queue for the keyboard, making it difficult to type fast, but despite all of the challenges, I was able to complete the game.

I did record it, although I need to test levels properly, the audio is a bit muddled. I don’t know if it’s worth watching it all the way through, I die.. A LOT. And stupidly. And don’t save anywhere near enough and have to repeat some parts over and over and over.. The stupid alien vine maze took me over half an hour as it was impossible many times to clearly see.

Also, it has my terrible DosBeep code, which of course sounds terrible. There ought to be some way to tell sound effects from ‘music’ as it seems they are coded for different durations and tones. But I don’t know what I’m doing, I’m just a monkey banging keys.

Another Pre-release of OS/2

IBM Operating System/2 Pre-release 1.10

In other exciting OS/2 news, I came across this previously un-dumped IBM Pre-Release of 1.10! It’s tagged for 08/08/88! No doubt very lucky for someone. The only mention I can find of this comes from Excel 2.2 for OS/2

B. Supported Releases of OS/2
Microsoft Excel for OS/2 is compatible with OS/2 Versions 1.1 and 1.2.
If you are running an early release of IBM OS/2 Version 1.1, you should
verify that your copy of OS/2 supports Microsoft Excel for OS/2:

    1. Open an OS/2 full-screen command session.
    2. At the OS/2 command prompt, type SYSLEVEL and press ENTER.
    3. Check the number listed on the line "Current CSD Level."

Microsoft Excel for OS/2 requires a CSD Level of:
    *  WR2030 or higher for IBM OS/2 Standard Edition Version 1.1
    *  XR2030 or higher for IBM OS/2 Extended Edition Version 1.1

If your release does not support Microsoft Excel for OS/2, use the coupon
included with IBM OS/2 1.1 to order your Device Support Supplement, or
contact your IBM dealer to obtain the appropriate Corrective Service Disks.

Of course, good luck finding any updates for this OS from 1988.

Presentation Manager Driver 4.37 (Debug)

It does look and feel pretty complete for a such an advanced beta. But was there any actual software for it? I have to wonder that given the note in Excel 2.2 was there a pre-release version Excel that was for this? Excel is dated 23/09/89, so maybe there was some fancy ‘executive demo’, with protected mode massive memory models? You have to think in that window prior to Windows 3.0 the spreadsheet pros would have demanded Excel on OS/2 (When did Lotus finally do 1-2-3?)

Excel won’t run on the IBM Pre-release

Of course, I had to try to run Excel on the pre-release. And not too surprising, it doesn’t run. From the command line it just reports a SYS0008: Not enough storage is available process this command.

There must have been something that had to have been distributed with this Pre-release and I suspect it was more geared towards end users. But I’m just speculating.

Hobbes saved!

There has been so much noise about the OS/2 Hobbes archives being removed, that the community has not only mirrored it all over the place (It’s a tiny 18GB), but the search database has been transferred, and it’s now usable over at:

Welcome to Hobbes (

Too bad physical releases are so out of the question, at least there was some outrage to get this saved before it died. Nice.


Otherwise, it’s been a busy week, and I know I owe the mainframe video, which I’ll work on finishing up tomorrow. Fun!

so I was excited to try this protoweb thing!

mjd -protoweb

I saw this video and I was like sold! I have this PowerMac 6400/180 so I figured this would be good. The problem was my network card was acting up so I figured instead of troubleshooting it I’ll just format it and go from there.

the machine is very much an Old World Macintosh, so that limits me from OS X. It’s 603ev CPU it’s not all that advanced either. I have an 8.1 ISO that I’ve been using under 68k emulation but the limit it has is old multimedia stuff ins t 68k compatible as nobody would imagine emulation putting 68k at speeds above a gigahertz.

I went looking for a 8.6 ISO, and that is where the fun hit me again that many so-called ISO images aren’t. Rather they are giant floppy disk images with the media headers and/or partition tables being obliterated. As an ISO they don’t detect at all, and as a giant floppy, of course they don’t boot as MacOS checks if it is on read-only media.

This ISO isn’t an ISO

very annoying

I did manage to finally find one that does work however!

working ISO

I forgot where I found it though. I did save it to, since I have another 5 versions of this downloaded, none of which will boot.

I should also add the MacOS 8.1 CD-ROM image Ive been using as again,l I have the same issue where so many are headderless ‘floppies’ and not actual CD-ROM’s that don’t work in Cockatrice III or an actual Mac using BlueSCSI.

MacOS 8.1 CD-ROM on Cockatrice III

Sorry the image shows in black & white, but as you can see from the CD-ROM background it is in fact booted from the CD-ROM. You can download it from here:

In no time, I was able to get online only to find that the power Mac plugin’s seem to be unavailable for anything and unsupported.

old netscape website

but the rendition of the old Netscape page was a treat!

Now I do have a Windows Surface RT tablet, and sure enough pluggin the proxy values, and YES the video site does work!

Warpstream on Windows RT

Very cool! So it turns out Protoweb can actually save all those old devices that work fine enough, but not fine enough for ‘Modern platforms’.

The Rise of Unix. The Seeds of its Fall. / A Chronicle of the Unix Wars

It’s not mine, rather it’s Asianometry‘s. It’s a nice overview of the rise of Unix. I’d recommend checking it out, it’s pretty good. And of course, as I’m referenced!

The Rise of Unix. The Seeds of its Fall.

And part 2: A Chronicle of the Unix Wars

A Chronicle of the Unix Wars (

Years ago I had tried to make these old OS’s accessible to the masses with a simple windows installer where you could click & run these ancient artifacts. Say 4.2BSD.

Download BSD4.2-install-0.3.exe (Ancient UNIX/BSD emulation on Windows) (

Installing should be pretty straight forward, I just put the license as a click through and accept defaults.

Starting BSD via ‘RUN BSD42’ and the emulator will fire up, and being up a console program (Tera Term) giving you the console access. Windows will probably warn you that it requested network access. This will allow you to access the VAX over the network, including being able to telnet into the VAX via ‘Attach a PTY’ which will spawn another Tera Term, prompting you to login.

telnettting into the VAX

You can login as root, there is no password, and now you are up and running your virtual VAX with 4.2BSD!

All the items

I converted many of the old documents into PDF’s so you may want to start with the Beginners guide to Unix. I thought this was a great way to bring a complex system to the masses, but I’m not sure if I succeded.


As it sits now, since 2007 it’s had 776 downloads. I’d never really gotten any feedback so I’d hoped it got at least a few people launched into the bewildering world of ancient Unix. Of course I tried to make many more packages but I’d been unsure if any of them went anywhere. It’s why I found these videos so interesting as at least the image artifacts got used for something!

But in the off hand, maybe this can encourage some Unix curious into a larger world.

Other downloads in the same scope are:


Since there had been some confusion on how to install MacOS 9 on OS X

I thought with this iMac G5, the least I could do is make a quick video of how to do it.

Low effort video

I’ve done the hard work of converting the eMac 9.2 install CD to read-writeable, updating the system folder, then converting that back to a read-only image so the MacOS install can happen.

I’ve uploaded the file over on ro-macos9updated.dmg.

The steps are somewhat simple basically download & mount the disk image.

Open up the prefrences, go into classic and select the

Then hit start to boot the image.

Then go and run the installer

Uncheck everything from the options

Customize the install and ONLY select Mac OS 9.2.2 & Internet Access.

The install took less than a minute on my G5

Go back to preferences, and stop Classic

Unmount the disk image, and open classic again & select the System Folder on the Hard Disk.

Start up Classic from the hard disk, and OS X will want to update the System folder

MacOS will want to run the setup wizard but since the ‘Bluebox’ isn’t a real Mac, I just cancel it

And then you are good to go!

Inside Windows 2000

part 1

A talk from Dave Probert on the design of the NTOS kernel. Shame Microsoft didn’t put this anywhere people could have found this 20+ years ago, just as a shame they never opened up NTOS like they did that even tepid Windows Research Kernel. It goes without saying this is the ‘Linux is a cancer’ generation, with the crazed idea that looking at Linux would contaminate Windows.




Too little, too late I guess. It would have been an interesting foundation a long time ago.

And of course the ongoing work behind the scenes making Windows fully 64bit compatible on the Alpha at the time.

More PS/2 upgrades! More RAM, More advanced SCSI!

So I had gotten this Boca Ram/2 card with 2MB of RAM, with space for an additional 6MB. Unfortunately trying to find matching memory has been a lost cause. Since the existing memory is 9 chip modules, I take that to mean it’s parity RAM, so I went shopping for much more available 3 chip modules.


I picked up 2x 1MB modules for £10.

Slotting them carefully into the ram card, taking great care as the clips are plastic!

4MB of ram slotted, made in the USA!

Now from what I can remember being told is to never ever ever mix memory types like this. But logically I have to think that 9×1 = 4+4+1, right? RIGHT?!

I copied the @7A7A.ADF onto the reference disk image, slotted the card and booted up to the config, and toggled the card to 4M

4M (4 SIMM modules)

I didn’t trust the auto-config, plus I just wanted to see what was there. Also I’ve always wondered if the PS/2 model 60 (or 30? 50z?) can slot higher density than the 256kb SIMM’s that IBM had used. I guess one day I’ll give it a shot.

Anyways thinking that this is about done, I save the config and reboot and now It’s Bocaram/2 issues.

Immediately, on reboot I get error 164.

164 POST detected a base memory or extended memory size mismatch error.

1. Run F1 Setup. Check System Summary menu for memory size change.
2. Run the Extended Memory Diagnostic tests.



Booting from the reference disk just crashes the PC.


Pressing F1 however does let you boot, ignoring the issue.

After a bunch of digging I found this zip file with some utils. And just guessing br2pmems ‘fixes’ the CMOS settings allowing the machine to boot normally.

So now it’ll recognize the 5MB of RAM, and just boot normally. GREAT. But booting the reference disk still hangs the machine.

Which then brings me to the next upgrade:

The IBM SCSI with Cache

The IBM SCSI with Cache aka the SPOCK. Since I ruined the one SCSI card, and ended up picking up a second card, but this time with the appropriate cable I’ve caused a massive market panic on Microchannel SCSI cards. Seriously check eBay, and you will see that the pricing has collapsed with many now selling in the £20-30 range. You’re welcome!

Not really wanting a 3rd SCSI card, but my eye saw this one with the cache RAM, and I figured if I wanted the ultimate PS/2 of course I’d want a caching controller. This looks to be the first rev of the PCB, but with the ‘hot fixes’ in place from the second rev. While the ROMs are stepping back to 1990, I don’t care much about the 1GB disk limit, as the BlueSCSI can emulate all the available devices in the chain, so I’m not losing anything in the way of capacity. This is a 286 after all.

Since the RAM card screws up the setup program, I have to remove it, and the old SCSI controller, re-configure the system with all the RAM and disks removed first. Then put in the new controller, and re-run setup.

I just accept the defaults, and reboot to check what happened. So far it looks good, slot 8 being near the middle of the PCB, and closer to the disk cage where the blue SCSI rests.

placehold all the drives!

Remembering that the IBM controllers inventory the disks backwards, the 380MB disk image on SCSI ID 6, is the primary boot disk. I didn’t set it to the full 1GB as I want to later see how older versions of DOS/OS2 work with this, and I know they have issues with disks bigger than 512MB, but I figured matching a disk that did exist in 1988 would be more realistic.

With the SCSI setup, I could put the troublesome Boca board back with the RAM, and get my system booting up with the new “faster” SCSI controller, and all that new RAM.

Old SCSI controller

Of course I did a few benchmarks on the old SCSI controller so I would know how much more awesome the new one is.

As you can see this is booted with my normal config.sys with a himem.sys and smartdrv from Windows 3.1 on a MS-DOS 5.1 install.

2,345.8 KB/sec With himem.sys & smartdrv
2,347.5 KB/sec with no himem.sys
2,316.6 KB/sec with runtime xmsmmgr & smartdrv
2,334.0 KB/sec with Windows 3.1 himem.sys no smartdrv

So, with these scores in hand, you can see that the penalty for various XMS memory access being turned on is there, but it’s nowhere near as massive as I’d have thought for performance. Even with it just being there, although again it’s so minimal.

Now for the real shocker:

2,079.2 KB/Sec

That’s right, the advanced card is slower. A good 11% slower. Well, that was disappointing. I’m still keeping it in the machine, as having a hardware caching controller was all the rage, just like Mach microkernels. Maybe it’d make more of a difference in a 32bit system, but it’s performance is very underwhelming. For anyone wondering, the WDC AC2340, is an EIDE 340MB hard disk, with a 64kb cache. Im sure it was considered very fancy, and fast for the era, and it’s nice to know that no matter the SCSI controller, the BlueSCSI blows it out of the water. Also keeping in mind that MFM data transfers are usually sub 400KB/sec, so this is much more faster.

Okay you have all this XMS what are you going to do with it?

Well, after I did manage to get this original copy of Word for Windows 1.0, I thought that it would be a good test. One fun thing is that it includes the ‘runtime’ version of Windows 2.11, which can also upgrade an existing install of Windows 2 if detected. Running Windows 2 on MS-DOS 5, does involve loading the setver command in the config.sys, and rebooting. Windows 2 cannot use XMS (more on that) but instead uses the older LIM EMS standard that allows a 64kb page to be viewed from a far larger card. Since the 8086/80286 still use 64kb segments it’s not all that crazy to use.

And that brings me to this great program EMM286!

It allocates a 64kb page in low ROM, and backfills it from XMS. So I give it 3MB, and now I have 1.3MB of XMS left, and 3MB of LIM EMS ready for Windows!

So now I have EMS & XMS! And didn’t have to get some pesky EMS board either. I am pretty sure you need device drivers to use EMS, so how do you use LIM EMS under OS/2 1.x? I have no idea. Probably not I guess?

Anyways I run word, everything is great, it sees extra ram. I exit windows, and unload EMM286, and ..

3.4MB of XMS available? Somehow I lost a megabyte of RAM from Windows 2?! I’m not sure what is going on, or why or how Windows even touched it. Needless to say if you want it back, you need to reboot.

DOS 10.21
494KB free!

That’s right 494KB free! I thought MS-DOS under OS/2 just used some stubs in real mode, and called back to protected mode. No doubt this is totally wrong, there has to be some weird version of DOS+OS2 that actually runs in real mode going on here. I know that ‘bimodal drivers’ were a thing, but it sure seems like there really is a ‘real mode OS/2’ kernel with MS-DOS tacked onto the side.

Windows 3.0 standard mode, 286 + 5MB of RAM

It’s annoying OS/2 can’t tell you how much ram it sees and what is in use, but at least Windows 3.0 can. It’s more than enough to run Sim City, clearly making this one of the more expensive machines to run the game as intended. With the added RAM it doesn’t thrash as hard, but having emulated disks probably doesn’t matter as much as access time is always zero, and it’ll stream data as fast as it can. You can feel the difference moving between tasks, but things like the OS/2 file manager that loads a view into every directory is still incredibly slow. What were they thinking?!


Back in the day this would have been an incredibly expensive upgrade. And is it worth it? The machine is still locked at 10Mhz. The FPU is also locked at 10Mhz, and you can feel it. The lightening fast disk access, despite it being some 11% slower is really hard to tell. Does the caching help at all? Applications don’t have to page in/out like crazy before as there is enough RAM to actually run them, but that is where the 10Mhz processor just isn’t there.

Just like the caching SCSI controller, I’m sure we’ve all heard how having that magical EMS memory would help out games like Wing Commander.

XMS/DOS High + EMM286 on the left, and just XMS + DOS High on the right

Well, I had to put them side by side, as I couldn’t believe it, but adding EMS made it noticeably slower. I was *NOT* expecting that. I should add that I used Vegas & this quick tutorial, on how to pan & resize one video to get them side by side. No doubt it’s not perfect but it’s enough to see that once the ship explodes, the performance on the EMS configuration is greatly throttled. It’s moments like this that makes me wonder is this something the caching SCSI card would do better implicitly? Or is it snake oil as well?

3MB is enough to load OS/2, and one application, just as Word v1 or Excel v2/v3 load just fine, but swapping between them is basically unloading one from memory, and loading the other back out to disk. It’s a shame RAM cost so much 1987-1992 as people really could have benefited from it. It’s just utterly bizarre that on such an outrageously expensive system that you even need RAM upgrade cards, it really should have been baked into the main logic board.

Bill Nye, the Microsoft C 6 guy

So, a while back I had found this up on eBay. As much as I’m trying not to buy old stuff I just couldn’t resist. And the price was just too good, I’d just have to forego going out to dinner for a week.

While looking around for something on Microsoft C, I stumbled upon this promo video for Microsoft C 6. Naturally I had to share it!

I had been using it to mess around with a poorly ported Hack 1.03, although I haven’t done much with that in a while.

One thing is for sure, that the old MS-DOS memory limits were becoming more and more of an issue. Sadly, they didn’t include the QuickC for Windows product which had the benefit of building in protected mode for access to far more memory, nor did they include any DOS Extender to even allow larger runtime access. Obviously you were expected to run this under MSOS/2 1.2 in this era. Although targeting OS/2 protected mode allowed easier integration with PharLap’s 286 based DOS Extender.

Since this was the OS/2 era, the Windows 3.0 SDK was a separate product.

There was another release, the 6.00ax version which included a DOS Extender, allowing the compiler to access 16MB of ram, as reported in this leaflet in a combined Microsoft C & Windows 3.0 SDK package.

The followup Microsoft C/C++ 7.0 addressed many of these shortcomings, but of course famously removed targeting OS/2. There was a later update that at least provided OS/2 compiled version of the binaries allowing you to run it under OS/2. I never tried to see if it could be paired with the OS/2 SDK, and manually made to generate OS/2 executables. I suspect not.

The larger thing is that Microsoft C 386 remained a ‘hidden’ product on Xenix, and the 32bit OS/2 and NTOS/2 betas.