Sunday, April 10, 2005

Compaq Presario R3000Z

Last week my order of new laptop I ordered from hpshopping.com arrived. It is Compaq Presario R3000Z with AMD64 3400+ MHz processor, WinXP home edition, 1 GB RAM, 80 GB 5400 RPM harddisk, 12 cell battery, 54g broadcom wifi + bluetooth, 64 MB Nvidia 440 Go, and 12680x1050 screen resolution. Not bad at all for total 1460 USD which I got 12 months interest-free loan from HP. The price is Employee Promotion Program as my employer has special with HP for their employees.

I did some tests such as leaving the closing and reopening the lid, ethernet (wired) link and wifi. They went OK, although sometimes the wifi interfered with my Linksys PCMCIA card that was on my another laptop (Tecra 8000. See my other blog about where and when I got this free laptop :-).

After a few days trying and installing some applications, I then repartitioned the harddisk using Norton's Partition Magic 8.0. I partitioned about 12 GB for Linux, 512 MB for its swap disk. I used Novell SuSe Linux Pro 9.2 for the Linux. Most of the hardware got detected (I was suprised that the touchpad even did work. I read somewhere on the Internet, the guy said it was kinda hard to make the touchpad work, but it was OK on my Linux. Perhaps because I use SuSe Linux 9.2?). For the wifi, as usual Broadcom does not provide the driver for Linux, but thanks to Ndiswrapper it could use the driver from Windows instead. But I still have problem even with ndiswrapper. Somehow, dhcp client could not get IP address, although the Wi-Fi recognized and found my Access Point (which is Netgear 802.11b) and found its MAC Address. I am not sure whether this is because of the kernel I use (oh, forget to mention that SuSE 9.2 comes with kernel 2.6.9, so I upgrade the kernel to the latest at this time, 2.6.11.7)

When I compiled the kernel and ndiswrapper, I used all the processor-specific optimizations by defining the environment variable CFLAGS and CPPFLAGS. My CFLAGS contains "-mcpu=athlon64 -mfpmath=sse -msse3 -m3dnow -m64 -mthreads", so is CPPFLAGS. No errors during compilation and everything went well. But I was still wondering why gcc could not recognize -m64 when I tested by creating a small C program and compiled it with CFLAGS as above?

The laptop's software packages come with Microsoft Works (not bad for many daily simple uses), Microsoft Money 2005 Standard Edition, InterDVD 4, RecordNow! CD&DVD burning software, Muvee Autoproducer and some other programs. Yes, I custom ordered the laptop with dual layer DVD writer.

The most I like from the laptop is its screen. It's so cool!. It is WSXGA 15'4 in screen, so it is so bright and displayed fonts are so crispy and bold. Even on Linux (which I set the resolution also to its maximum allowed, 1680x1050), it really rocks!

The processor uses powerNow technology from AMD. During normal use (which takes most of the time), the clock is adjusted to low (about 700 MHz). According to AMD spec, the maximum clock on Athlon64 3400+ Mobile is 2.2 GHz. But I haven't been able to test to make the processor reach its maximum speed. I think when it is rendering video it may go to that speed. When the CPU increases its CPU clock, the laptop gets hotter and this will trigger the CPU fan to blow the hot air. So far, I have not experienced the laptop goes too hot. May be if I am running Doom3 or Half-Life 2?

What think I don't like from the laptop is its weight. It is 2 times heavier than my IBM T40 laptop at-work. Well, what the heck, I don't really intend to use this laptop for mobile, but mostly to make me more flexible wanding around with it and still be able to do my hobby (hacking :-)

Overall, I love this laptop. I really recommend this for people are seeking a balance between budget and performance. Besides, it supports 64-bit processing, so when Microsoft finally releases its WinXP officially we still are not behind and not need to upgrade our hardware so the workhorse can still be used for few years (until IA32 finally obsoletes and a new architecture comes).

Saturday, April 2, 2005

How Physicists contributed to the Internet

Many people don't realize that their daily internet life has been affected more or less by works from physicists. Do you know who is the inventor of word-wide-web (HTTP, HTML and URL things)? Tim Berners-Lee, and he was a physicist working at CERN in europe. One of the gurus in TCP? Van Jacobson, who was working in high energy physics at Berkeley's Lawrence Laboratory.

I believe many physicists did contribute for the improvement and inventions of the current TCP/IP and other protocols currently in use.

Wednesday, March 23, 2005

Computer Reuse Through Linux

One day I found a laptop dumped in recycle bin at my office. It is Toshiba Tecra 8100 with Pentium3 450 MHz, 64-MB RAM and 12 MB harddisk. It had Windows NT in it. I took it home, reformatted it with my SuSE Linux 9.2. Well, the memory seemed not enough, so I went to ebay.com and found somebody was selling the 128 RAM SIMM100 for around 20 bucks. Not bad, I though. So I bought it and installed it on the laptop.

I got 192 MB now so I could run the GUI (I use KDE, but also added many GNOME libraries to run GNOME-based applications). I then downloaded the latest kernel available at that time (2.6.10). I also bought Cisco Linksys PCMCIA WLAN card (WPC54 SpeedBooster). Unfortunately, Linksys has not provided the driver for Linux yet, but luckily there is ndiswrapper downloadable somewhere. So I copied the driver for Windows to my Linux, run the ndiswrapper and ...voila, the wireless card worked. Well, still had problem here. Apparently, there was a conflict between ndiswrapper and ndiswrapper. I rebuilt the kernel and disabled sound drivers, but still sporadically the ndiswrapper did work very well (sometimes, the WLAN lost connection). For your info, I rebuilt them with specific processor criterias enabled, such as mcpu=pentium3 -msse and mfpmath=sse.

A few days I go, I gave a try to use kernel 2.6.11.5. I even rebuilt Krolltech's QT and many libraries. After many days of recompiling, I successfuly made the wireless work with sound drivers. I was one of the happiest days in my life making reuse the old laptop. I have been using the laptop for many of my daily activities, including browsing, reading emails and even a lightweight server. Yes, it is a server. Imagine if I use Windows for this purpose, I might have burned the laptop to the hell for its slowiness.

The laptop has SSH server, FTP, Telnet and many other services. I even also connect my external USB harddrive, thus I got additional 12 GB of space for storage. Not bad at all.

At work, I also partition my other laptop (it is IBM T30 with 512 MB RAM and 40 GB of total space). I parition 6 GB for Linux, and the rest for Windows 2000. You know what? I ended up using Linux for my work activities almost everyday. Linux is really cool, and I have learned a lot about many things because of opensource applications and tools available from the internet.

I really thank people outthere who have developed such great operating systems, applications and tools.

Thursday, March 3, 2005

Got Answer from one of the 'Hacker'

A few weeks ago I modified an article about SHA-1 on www.wikipedia.org by adding a link to another page telling a brief biography about one of the SHA-1 hackers, a chinese researcher name Xiaoyun Wang. After a few minutes, somebody removed the link and even the new page I added due to infringement of copyrighted materials.

I was suprised, but then I sent email to the researcher asking wether she objects my writing. I got a reply few days later saying that her team and the university (Shandong University of China) are going to create a new website dedicated to this security stuff. Well, she did not really answer my questions, but at least I got a response from an expert and Ph.D in security.

Let's wait and see how their website and papers will look like.

Rebuilding KDE made Easy!

After a few months not checking KDE website (www.kde.org), two days ago I revisited the site and found an interesting tool for KDE 3.3.2: Konstruct. The tool is easy to use and is designed to build (checking components and to download the missing ones, configure them, compile and link the whole libraries and component).

The only command I needed to execute is:

cd konstruct/meta/kde; make install

So easy to build now. If I recall, it was giving me hard time to recompile my KDE (it was 3.3) on my IBM Laptop T30. I had to download all *.bz2 files (plus qt-x11 libraries), extract them, reconfigure and compile one by one.

I am still having problem though when compile them on my 'free' Toshiba Laptop Tecra8100. Somehow, one component (Kppp) complains about 'regfree' and some other procedures altough I have double checked the Kpp*.cpp has "#include ". Anybody knows how to resolve it?

Friday, February 25, 2005

Crack in SHA-1 code 'stuns' Security Gurus

Three chinese researchers said on February 14, 2005 that they have compromised the SHA-1 hashing algorithm at the core of many of today's mainstream security products.

In the wake of the news, some cryptographers called for an accelerated transition to more robust algorithms and a fundamental rethinking of the underlying hashing techiques.

"We've lost our safety margin, and we are on the edge," said William Burr, who manages the security technology group at the National Institute of Standards and Technology (NIST).

"This will create big waves, in my opinion," said the celebrated cryptographer and co-inventor of SHA-1 (Shamir hashing Alg.), Adi Shamir. "This break of SHA-1 is stunning," concurred Ronald Rivers, a professor at MIT who co-developed the RSA with Shamir.

RSA is a public-key cryptosystem for both encryption and authentication; it was invented in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78]. Details on the algorithm can be found in various places. RSA is combined with the SHA1 hashing function to sign a message in this signature suite. It must be infeasible for anyone to either find a message that hashes to a given value or to find two messages that hash to the same value. If either were feasible, an intruder could attach a false message onto Alice's signature. The hash functions SHA1 has been designed specifically to have the property that finding a match is infeasible, and is therefore considered suitable for use in this role.

One or more certificates may accompany a digital signature. A certificate is a signed document that binds the public key to the identity of a party. Its purpose is to prevent someone from impersonating someone else. If a certificate is present, the recipient (or a third party) can check that the public key belongs to a named party, assuming the certifier's public key is itself trusted. These certificates can be held in the Attribution Information section of the DSig 1.0 Signature Block Extension and thus passed along with the signature to aid in validating it. (See section Attribution Information section in the DSig 1.0 Specification.)

The signature section of the DSig 1.0 Signature Block Extension is defined in the DSig 1.0 Specification. For the RSA-SHA1 signature suite, the signature section has the following required and optional fields.

Who are these three chinese researchers? One of the member, Lisa Yin was a Ph.D student who studied under Ronald Rivest (RSA inventor) at MIT. Another one was responsible for cracking the earlier MD5 hashing algorithm (also developed by Rivest in 1991) which happened in August 2004.

To learn more about MD5, please visit http://en.wikipedia.org/wiki/MD5. For RSA: http://en.wikipedia.org/wiki/RSA, and for SHA-1: http://en.wikipedia.org/wiki/SHA-1

The open-source code version of the algorithm can be found in http://www.cr0.net:8040/code/crypto/sha1/. Samir et.al published their paper at ACM forum: The RSA Encryption Algorithm, R.L. Rivest, A. Shamir, L.M. Adleman, "A method of Obtaining Digital Signatures and Public-Key Cryptosystems", Communications of the ACM, v. 21, n. 2, Feb. 1978, pp 120-126.