If you’re like me you attend to go back and forth with Operating Systems. When this happens you have different boot loaders for the different OS/s. Windows uses the Microsoft Boot loader and Linux uses Grub or Lilo. I hate having to switch back and forth so I found a very nice alternative. The alternative is a different bootloader is flashed into a Option ROM and then called when the BIOS runs the INT 19h/INT 18h interrupt call. I’m layman’s terms finds the closest boot code. Or for the end user tricks the system to think it’s loading BASIC or the BIOS front end. The Boot loader I am talking about is called the Plop Boot Manager. I really like this not only because of the option to have it load from a Option ROM but you can boot legacy systems that do not have a bootable USB option or use the bootloader from a PXE environment.
Now how can you add this Option ROM. Well every device in a PC uses a Option ROM device but are in use except one device that is mostly over looked. A Ethernet card will have a empty IC socket. This empty IC socket when populated is used for booting a OS over a network. Mostly used for PXE or what have you. You can flash a chip that holds the bootloader and have it in the card. Some PNP BIOS systems will have a option to set the LAN as a bootable device. Older systems will need a bootable image and will use the INT 19h/INT 18h interrupt.
This doesn’t mean it will work with any Ethernet card. You can’t use integrated Ethernet that is built into a motherboard since the built in Option ROM coincides with the system BIOS. It has to be a add in card and only a few can be used with out a IC programmer. For a example of a prime card of choice is the Intel 10/100 Pro. They have a PLC type socket and again if you’re like me and when you tear down broken motherboards you keep the old BIOS chips if they’re removable. Now it doesn’t mean you have to use this card for Ethernet use. You can ignore it, disable it in Device Manager or skip the drivers. There are also a few ways to flash it. Some people have had success using a BIOS flash tool from AMI. I myself prefer to use a Linux environment and a program called FlashROM. You can also use a version for DOS but your mileage will very. I prefer Linux because I can get the exact hardware ID and Address so I don’t end up writing to my GPU or BIOS.
In all you can write crap all over the MBR on the hard drive and still be able to boot the system.
Same as before but tried a modified line simulator circuit. Uses a 1uF cap, 9v battery and a 330 1/2 watt resistor. Works very well and now I can hear the modem speakers chirp.
I tried using some different programs in Linux to use the modem such as pppd and wvdial with no success. I also tried using screen for giggles and indeed I can issue AT commands with it but blindly but still no connection. I’m starting to think I might need different modems. If I can find some 74HC942 chips I can build some nifty 300baud modems with hardly any parts.
Tried to install a native BBS server for Linux called MBSE BBS. Damn thing was coded by a blind man. Took forever to reverse engineer the install scripts and when all said and done it doesn’t work. Looks like I’ll have to find another way.
Tried numerous ideas and such for making a simple Line simulator. The only one that kinda works is just using a 9volt battery and a 1/2 watt 330 ohm resistor on the Ring (red) wire.
Now one system has Linux with Minicom and the other has Windows XP.
The Linux box was a bit harder to setup due to a driver issue with the modem. I came across a Ubuntu guide that did the trick since after all Ubuntu is a bloated copy of Debian. I installed Minicom and ran the config to select my modem. In this case its not a ttyS but uses its own handle of /dev/537.
I fired up HyperTerminal on the XP system and with both systems in a terminal application I issued some simple AT commands. On the XP box I issued ATX0D and as fast I was ale to turn to the Linux box I issued the ATA command. They shookhands so to speak and yet something odd happened. The XP box had a bunch of scrolling garbled text while on the Linux box nothing happened. Guess I’m getting somewhere with this. Hopefully tonight at work I can ask a friend that knows more about analog phone connections and see if he holds a answer. If anything I might have to try a different approach by using PPPd, finding some real modems and stop mucking around with some WinModems or buy off of ebay a real phone line simulator.
Tomorrow I need to do some rearranging and start on setting up a BBS.
As most know my Tinker system is a oldie but a goodie. Since most of the hardware is from mid 2002 to 2008 and over time Linux has dropped support for a lot of hardware I decided to go with Debian Linux Lenny. Granted it’s old but I can still run new software with it by compiling the source. Good news however the Dial-up modem that is in this thing is X100p compatible so I can use it as a FPX card and have my own private PBX if I wanted too.
Anyway, since Debian has removed the repo to Lenny I had to find a work around that didn’t involve creating a bunch of CDs or playing with a jump drive. All you need is the online installer image.
Download and burn the image to a CD or use UNetbootin to use a jump drive if your old system has a USB boot option. If your system does not have a USB boot option and want that function then check out PLOP Boot Manager.
Boot up the system with the selected media of choice and install as you normally would. I prefer to use Expert mode. When it gets to the point on a software repo just continue and skip the repo selection. Finish the install and make sure to install Grub or Lilo and reboot. Login as ROOT and edit the APT sources file located in /etc/apt/sources.list Hash out the CDROM entry and the default entries and add the following,
deb http://archive.debian.org/debian-archive/debian/ lenny main contrib non-free
Save and then run apt-get update. After APT updates then you can run tasksel to rerun the installer. From there you can select graphical desktop or what have you and install what is needed.
Now if you do this you need a decent firewall if you plan to have a internet connection with it after you get everything installed.
Well, my day started by installing Debian Linux on the tinker system. I tossed in a old 120GB drive and started installing Linux. After spending a couple of hours installing, updating and tweaking it to my needs I rebooted. Little did I know I used the wrong drive…
However this was really a blessing in disguise because the second drive is locked up from a password.
The hard drive was pulled from a old system that was given to me. The BIOS had a user/supervisor password set and I didn’t know the password and clearing the CMOS didn’t wipe it. Reason being the password was written onto a Option ROM or something like that physically to the hard drive. If you tried to boot the hard drive on a different system the BIOS reports it as non-bootable and locks up or if the other system uses the same version/brand BIOS it will ask for a password. In other words the hard drive is useless as a primary active storage. There is a work around like using ATA commands to wipe it but a waste of my time. It’s not a total loss since I keep backups and I’ve been wanting to switch the system over to Linux anyway since I’m tired of fighting windows to do my bidding. The only issue with using Linux is the file sharing with my main desktop that uses Windows 7 but I can fix that with a simple local FTP server or even better by putting my NAS back together.
I have been still trying to cast parts for the CNC with HDPE plastic. I need to make some better molds. I’m currently just using two pieces of plywood and a rolling pin to make the pieces flat but there not truly flat because a bunch of high spots and if I was to use a router to flatten them the parts would be too thin.
The computer project for connecting two dial-up modems with a Line Simulator isn’t going too well. The Simulator I tried isn’t working right and it doesn’t see much of a dial tone. So it looks like I need to add a fake dial tone to it. Also for some reason Windows NT 3.51 doesn’t like the system hardware so I just left XP on the hard drive since it was already per-loaded.
Still waiting for the Oscilloscope kit to show up. Can’t wait for it to show up.
I miss the simple days of computers and I attend to relive the past at times. I have a few old computers. Some of them have Dial-up modems that as we know are “useless” unless you know how to use them in the world of today. We’re in the digital age and most Analog is pretty much gone to a certain degree. For kicks I plan to setup a local private telecom exchange. To achieve this I will run a Linux host with a dial in server that will also be connected to the home network via Ethernet while a client system running for giggles Windows NT 3.51 that will connect to the host via a dial-up modem. Now how would someone make a analog modem connect with out the proper hardware? Simple, a circuit that will add the proper power to the line and simple AT commands if needed. Best from what I can tell I can make the host listen for the AT commands to connect and give a IP address to the client and then share the Ethernet connection. I don’t know exactly but I will find out. Might also give me a reason to host a old school BBS system.
The host will be my tinker system. Just need to toss in a extra hard drive and install Debian Linux. Also I will need to toss in a Dial-up modem. The client as said before will be running Windows NT 3.51 or maybe Windows 2000 Professional if I have too many hardware issues. The circuit for the phone line is a simple Line Simulator that uses a 500ohm resistor, .47uF cap and a 12volt power supply. Instead of using a wallwart I will use a unused 12 volt lead from the tinker system. It should be fine since the modems are isolated and also since it will not be connected to a real phone line I don’t have to worry about a power surge. However if a Wallwart is needed a 2200uF cap should be used on the positive and negative side to cut out the ripple from the AC voltage noise.
+ | | - 500
| | | R |
| 12V |
Be nice if I had a dumb terminal or even a teletype.
Instead of using Wood or Metal for the CNC I am going to use HDPE. Today I was in the kitchen melting and forming the plastic. I was pretty much trying out different ways on molding it. The best way I have found is to flatten it out before compressing it to cool. I used a old metal pipe as a rolling-pin to flatten out the molten plastic. After compressing it and waiting it to cool I pulled out my new mini 4″ Y-Mite table saw and went to work. The little saw eats the plastic like a hot knife cutting butter. After cutting some parts I noticed there are high spots and ruff spots. To fix this I plan to use my hand router to flatten out the surface of the plastic. I want the overall thickness of the plastic to be quarter inch thick.
The awesome thing about using old milk jugs for this is it’s free and what left over trimmings I get from cutting parts I can remelt them and make more parts and panels. I can even sweep up the plastic dust and reuse that as well.
Well the cheap rotary tool I wanted to rob the chuck from is a no go. Cheap soft aluminum is what it was made out of and trying to remove it got chewed up. So now I’m thinking to make my own. When you think about it the unit is nothing more then a shaft with threads on the outer and a nut on the other end that compress the collet. The collets I have from the cheap tool are brass and will work nicely. I just need to find a piece of solid round stock and attempt to drill it out with out a lathe. If anything I’ll just buy the Dremel chuck (Part number 4486).