Fighting with computers

Recently, I was involved in a development where remote access to a serial port was required. I was doing my development with a Rabbit core and I needed to get Internet access to a serial device and to simulate a serial port on the host PC. I learned that you could use RFC-2217 which is an extension to the telnet protocol. I went to nabble to get some help but I found out nobody seemed knowledgeable about that protocol. So I did my job, and when I got it running I wrote an article for an engineers magazine. Once I get the "go" from the editor I'll let you know where it is published. I used with quite success Fabula Tech's Serial Port Redirector which is RFC-2217 compatible, but it is not free. For a free redirector you could use HW-group's Virtual Serial Port but be warned this latter software does not handle break signal generation. The same thing applies to Digi One SP device that, although the manufacturer claims it to be RFC-2217 compatible, it is not ca...

I was approached by a lawyer whose client was an employee fired for porn surfing. The company threw some logs at the employee as a proof of his wrongdoing. However, the employee rejected these claims as erroneous and sued the company to get his job back. I was asked to double check what those logs really showed. Just to play safe, I decided to conduct my "research" from my home network instead of my employer's network. What I learned was somehow baffling, as most of the logs appeared incomplete showing only one small gif or jpeg per site with almost no html pages visited. While some of the images had some sex contents most didn't. Still, the names of the servers talked by themselves about the contents of those sites. Multiple visits to the same gifs suggests no caching on the browser, or ..., multiple clients. It reminds me the Migmaf trojan but that was way back in 2003. Unless I get access to the employee's computer I cannot make a better judgement now. At any r...

I did it again: I fell for another new toy. This time the winner was the inexpensive Acer 3002 WTMi that packs quite a decent feature set into a small size and weight. I won't bore you with the details, but have a look a it if you're planning to buy a light small form laptop . It comes with WinXP Home Edition installed and, as usual, you'll have a hard time if you try to get a refund on it. Microsoft's tax seems to be a burden if you buy a laptop either you like it or not. Although I've installed SuSE Linux 10.0 I'm not very happy with the results for the moment. First of all you need not to use APIC for the installation to start. The system installed very quickly and it did one of my FAT32 partitions to shrink without any problem. It took less than 15 minutes to get the install finished. What I've got working are graphics, WiFi, Bluetooth, Ethernet, DVD-RW and synaptics mouse (the latter even better than with Windows) but sound is missing (it looks like an...

Dealing with software you cannot change is a risky business. This time I need to emulate a serial communication to fool the software to think it is talking to a directly connected device. I have tested several serial port emulation software with not much luck. However I have to tell you the guys at Fabula Tech have a winner with their Network Serial Port Kit . It worked like a charm, providing a way of sharing a serial port on one computer so a second computer could use it remotely through a network connection. Not only this, but these guys have a fantastic on-line support chat that, contrary to most of them nowadays, they are knowledgeable and they solved my problem at the first shot. Really recomended product and service. However, I needed a solution I could throw at a client's computer even without network card. I looked around for serial device servers and Digi One SP looked a good choice. I bought a couple of units to see if they could really replace a serial cable (you repla...

I've learned about an interesting site on the net: Cosmopod.com What is it about? In a nutshell Cosmopod offers you a free remote KDE desktop, either using a Java-based client software or the (also free) nxclient software. I do not know how reliable the service will be in the long run, but my initial tests are very good. Although services like writely seem promising, I'm really impressed with Cosmopod. They also offer a 1GB email account with your desktop. You may like it, I do.

One of my current projects requires to provide IP connectivity for an electronic system. Some power can be borrowed from the base system it will be plugged into. A small, low-power system will do it. So after considering several options (like Lantronix Xport ) and provided I needed at least two serial ports, I settled with a Rabbit Semiconductor core module. They offer different prebuilt cards you can plug into your design. Rabbit core modules can be programmed using Dynamic C . They include a TCP/IP library so you can program them using an ad-hoc sockets interface. Sample source code is provided and it generally is quite straight forward. I did have a problem when using a non specified (zero) source port for several destination ports different than 80 or 23, I do not know why. Rabbit 2000 and 3000 processors are both successors of the ancient Z80 , an eight-bit microprocessor developed by Zilog (a company founded by some former Intel engineers that decided to do a better 8080). Z80 w...

I've never heard about a "flash sale" before, but recently I saw an ad on a local retailer's website offering a cute Toshiba laptop (M50-137) for a really low price only if you buy it on December 23rd. They take 200 Euro off the list price of 1200 Euro. I thought it was making it sweet. The system was a 1.7 Ghz Pentium M, with a WXGA Ultrabrite 14" display, 1GB RAM, 80GB HD, Wifi+Bluetooth, built-in SD-card reader, and a multistandard optical unit (DVD+-RW/DVD-RAM) weighting 2.4Kg. I took the deal and I picked it up at the local store. It took them longer than the advertised delivery time but eventually I got it home. First impression was good, system was fast and quiet. Sorry, you cannot get along without accepting the Windows blue thing: You have to provide some user and location data so Windows gets happily installed. Till you do this, SuSE Linux repartitioning failed to work. After that, I successfully installed SuSE Linux 10.0 and it almost worked fully. I ...

I was recently approached by a company willing to give new life to old security equipment. The system had a proprietary serial bus, but the manufacturer refused to disclose any information about it. Provided it was more than twenty years old it should not be a big challenge. However, figuring out the details of a serial communication you know nothing about will require some nice tools. This time I bought a nice USB oscilloscope . It's only 1 Mhz bandwith but fast enough for my needs in this case. With it I was able to capture bidirectional communication (as it is dual channel) and start the process of figuring it out. Just looking at the scope signals will tell you the encoding and bitrate (look for the shortest pulses, they are likely single bits and its time-length will tell you the bitrate). Serial communication used to be mostly asyncrhonous, and this was also the case. Once the time duration of a bit known you can figure out the data length and wether parity is being used or ...

I've just installed in a couple of systems I use. I decided not to do an upgrade from previous versions. It's nice you can use /home partition from a previous install so you can keep all your bookmarks and email and documents without too much trouble. A bit disappointing is that, still, java applets look bad (due to huge fonts) and that it cannot play almost any media file out of the box. But here is the cure . As for the rest, the system seems to be quite fast and stable. However, it will not be until some weeks have passed that we may have an informed opinion about this release stability.

Every time I build a new computer or I rebuild and old one I run into trouble. This time I transfer my old computer to one of my children and I bought a new ASUS Pundit-R with the cheapest Celeron I could find (a 2.4GHz one). Because my kid wanted to play games I replaced the ATI Rage 128 16MB RAM with a NVIDIA 440MX 64MB RAM I had lying on the drawer. However, I needed to get a new fan before as the old one on the card was making a lot of noise. Once the installation blues was over and the kid started playing he came back telling me that the system was freezing. A quick check-up showed the new fan was not properly fitted, so I removed the card and I re-attached the new fan (with funny LED's by the way). Minutes later, same problem. Ok, over time I've developed the attitude that the best brand of hardware is "brand-new". I was not 100% sure the card was ok so I went to the shop and I bought a non-NVIDIA graphics card. This time it was an ATI Radeon 9250 128MB RAM and ...

I've been using MPlayer quite extensively since I built my digital satellite receiver two years ago. I use MPlayer to play AVI/MPEG/MPEG2/OGM video files and I use MEncoder to actually create such files from MPEG2 broadcasted shows. These command-line tools that are both great and free software. Tools are based on standard video codecs and there is even support for commercial codecs (provided you get their dll files). I've used MPlayer on Windows, Linux and OSX without any problem. If you are a perfectionist a great deal of fine tuning of codecs parameters is possible. If you are "good enough" guy (as I am) you'll be pleased with default behavior most of the time (both in terms of computing speed and output quality). MPlayer is a program to play video/audio files that can also dump audio to a file. MEncoder allows you almost any transformation of your multimedia files (video+audio) plus different filtering options and limited stream cutting. My main use is to rec...

This distribution is available on ftp.suse.com for a month or so. You can dowload the installation DVD or you can do an FTP-based install by booting your computer with a small (60MB) ISO image. I've been using SuSE for three years now and I am, most of the time, quite pleased with it. It is my main distro and I like to have DVD full of software I can install without having an Internet connection. I do like the online update feature too. I have been upgrading my systems every now and then, mostly because newer KDE versions use to inlcude lots of fixes and new cool features. But when I tried 9.2 to install in my trusty but old Toshiba Satellite (128MB RAM only) it took around 6 hours. Afterwards the system took, everytime, a lot of time to boot because it froze for a long while on udev. And when it booted KDE was almost useless as it was slow to a crawl. The system was still acceptable, but slow, on SuSE 9.1. Because I had an Ubuntu install CD around I used this instead and now my ol...

After five years of trouble-free operation with my 11Mbps D-link DWL1000-AP 802.11b wireless access point I decided to upgrade my home wireless gear. The USRobotics USR-8000A router with print server and the access point were replaced by an SMC2804WBRP-G that contains a print server (for USB printers), 54Mbps 802.11g wireless access point, four ports FastEthernet switch and router, all in one nice box. My initial research on the net told me the product firmware was quite poor, with lots of users reporting different problems. However, because the retail price was under 100 Euros I decided to give it a try. The results: I configured the router off-line and then I just switched the old by the new gear on the fly. The p2p software I was running on a server continued running as happy as before. I was a bit dissapointed as the unit's current firmware does not provide fixed IP mapping, this can be a problem. After some hours of happy networking my son complained an streamed sh...

These holidays we've got some new stuff to play with. I'm very impressed with the new Creative Zen Micro , which is a harddisk based 5GB MP3 player plus FM radio plus voice recorder. It looks cool, it sounds superb and the software just works. Very nice too is the new Muvo (same capabilities but Flash-memory based, ours is only 256 MB). But the star has been the PB1600 video projector. It really delivers a great image for either DVD or VGA. It's 800x600 DLP-based but our 1024x768 iBook displays just fine. Now I need to get a projection screen to get the best result.

I live in a flat in a six storey building close to the campuses of two universities. As parking and traffic really suck around here I decided to get a bike. But lacking of parking place the obvious choice was to get the bike back home with me. You just cannot park it in the streets if you want to keep it for a long time. The problem was, then, to get the bike from the street to my flat. I've seen some people tilting bikes front-wheel upwards so they can fit it in the elevator but it didn't seem to me very convenient, and then you'll need some real estate inside your home anyway. I've learned about several brands making foldable bikes ( Dahon , R-M , Brompton ). Minutes later I've learned too that this stuff was expensive . I finally settled with a Dahon's Vitesse 3D for 425 Euros. It was a trade-off (and one of the less expensive alternatives) between folded volume, price and comfortable ride. I'm quite happy about the bike although I still think i...

January 2005 issue of Circuit Cellar Ink magazine contains my article titled "Build a Digital Video Recorder" with some clues about doing exactly this. Some days ago I was told some the systems that were cloned using G4U software seemed to have a lousy filesystem now. As the problem seems to be repeatable, it looks that the cloning process was not flawless for reasons yet to be determined (I'm in the process of finding out).

My kid's computer harddisk was dying last week. It booted up and it worked but sometimes after a clean shutdown CHKDSK was triggered on next boot (they use XP pro). The check was reporting some damaged sectors and I knew a replacement was due. I better do it now or I will have to reinstall everything from scratch. I went to the shop and I've got a new 160GB Maxtor drive. But, as usual, things were not exactly smooth: Old drive was a 40GB IBM drive with a single FAT32 partition. I wanted to get a bigger partition as the new drive was larger and I wanted to copy the old winxp system onto the new drive. Unfortunaltely, due to some defective clusters, G4U software stopped after copying only 6 GB and the result disk was unusable. G4L also failed because of the same reason. I borrow a copy of Ghost 2003 for DOS just to discover that I needed a boot floppy to run it and that my floppy drive was not working and full of dust. I got rid of the dust from the floppy and it eventuall...

My last project dealt wih the use of 1U rack-mounted PCs. Once the software was ready for deployment I needed to find an easy way to get the operating system and applications loaded onto the systems and I was looking for an easy and fast way of doing it. The units I am using are manufactured by Supermicro and they have no floppy or CD-ROM but are equipped with dual Gigabit Ethernet ports and USB 2.0. While booting the system up from a USB CD-ROM was possible this was leaving me with the task of manually configuring each unit. I've used in the past Symantec's Ghost software for harddisk clonning and I've found it quite useful. But to be able to use it in this case I would need to boot these computers out of a floppy disk or specially crafted CD-ROM that I don't have ready. On the other hand, a Ghost license will need to be purchased. Browsing around I've found a couple of projects G4U (Ghost for Unix) and G4L (Ghost for Linux) that offer you a ready to b...