July 2004 Archives

I have been looking around for Linux solution to create web page thumbnails. And, I found nice weblog entry which gave me push in right direction. However, I wasn't quite happy about hard coded values (sleep especially), so I started re-writing it.

Result is webthumb, a simple shell script with small number of prerequisites:

• vncserver
• mozilla-firefox
• HEAD (part or LWP perl library, it can be commented out)
• nc (netcat, to simulate web server)
• xwininfo (standard part of X-clients)
• xwit (not so standard command, but very useful)
• import (part of ImageMagick package)

Improvements include signal handling (so you can press CTRL+C to abort), support for dynamic display from vncserver (which enables more than one webthumb to work at the same time), fixed Window ID parsing (and more portable, I hope, please report problems), and special JavaScript+frame set+http server in shell hack to enable wait for page to load.

Aside from that, I must warn you that it won't work well with pages which have meta refresh or 304 redirect as first thing they do. Just point webthumb to redirected page and everything will be well. Here are also some examples: cnn.com, www.ffzg.hr, www.foi.hr, www.rot13.org/~dpavlin, www.linux.com, www.linux.hr, www.monitor.hr, www.pliva.hr, www.perlmonks.org, www.plivamed.net, www.plivazdravlje.hr, www.postgresql.org, prognoza.hr, www.rot13.org.

Possible usage include creating of animation from sites that change often, showing web page in different resolutions easily, or showing pop-up thumbnail image of site before user click on external link (I plan to do this with my home page).

Update: change link to subversion version (always latest one)

What can be nicer than two hour nap and a big cup of coffee? Good music? What is unusual in this situation?

I'm sitting at Frankfurt airport. I had nice two hour nap (after exhorting trip from Boston) and nice cup of coffee. But, real reason for this entry are noise cancellation headphones that I bought in Detroit while coming back. They are powered by one AAA battery, and they really work. Perhaps Bose model for $399 is even better, but this cheap model for $60 is worth every dime also! They actually make transcontinental flight something bearable. I would recommend them to anyone who had to spend more than several hours in airplane. They don't cancel all outside noise, but airplane engines and noise from bar is almost gone. And, to my surprise they also work without any background music.

I met really fun student from Korea on the plane who told me that technology behind this headphones is the same as echo cancellation in analog telephones. The logical question is then: why don't all headphones in airplanes have that? I can't believe that mass-production of such headphones wouldn't drive price down enough so that we have them everywhere. But, than again I am just guessing and I might be wrong.

If you are wondering where is weblog entry with pictures from Boston, I moved it to separate USENIX blog where it belong.
I also had comment that my English suck. Well, I know that I'm not native speaker. But, you will have to bear with me. On the other hand, at least somebody is reading this weblog :-)

So, USENIX Annual Tech is over, and I will be heading back to Croatia. However, I had to take photo opportunity before that, so here am I in front of MIT dome...

Here is also a nice squirrel which I met there (so that you can't say that I have just pictures of myself!).

Pa, sve se jednom mora završiti. Tako je i sa USENIX-om. Dakle, ovo je stvarno zadnji dan. Trenutno je pauza za ručak, i mislim da ste primjetili da su moji zapisi postali kraći: sa jedne strane predavanja su interesantna, ali ne toliko da bih napisao komentar, a sa druge strane umor konferencije me polako sustiže.

Jučerašnji BoF sessioni o Linux-u su bili zgodni (pričao je Miguel de Icaza o Mono projektu (Open Source .Net za one koji neznaju o čemu pričam), čovjek ima jako smješan izgovor).

Danas sam propustio predavanje o Debian-u da bih mogao biti a predavanju o različitim low-latency načinima povezivanja clustera (Gigabit Ethernet, 10 Gigabit Ethernet, Myrinet, SCI, Quadrics i InfiniBand). Nisam sasvim siguran da ću bilo što od toga vidjeti uskoro kod nas (osim naravno Ethereneta), ali bilo je zanimljivo.

Konferencija se polako pakira (valjda zato što ljudi koji odlaze danas moraju otići iz soba do 12 sati), čak se i wireless mreža uskoro prestati raditi (uh! kako li ću to preživjeti? Pretpostavlja da ću morati platiti $10 za internet u sobi!). Sve u svemu bilo je zanimljivo i neočekivano naporno.

Sutra imam slobodan dan koji namjeravam iskoristiti da vidim barem nešto od Cambridge-a i MIT-a (valjda ću nekako uspjeti stići tamo), a onda radom zorom u nedjelju krećem na svoj 28 satni povratak (+/- 6 sati koje ću dobiti mijenjajući vremenske zone).

Broj object storage servera se određuje po tome koliko bandwidtha treba klijentima.

Lustre 1.0 zapravo nije baš spreman za deployment, ali 1.2 (kada se pojavi free verzija) će biti. Naime, ls -l u verziji 1.0 je skoro batch job :-) Inače je cool. Naročito će biti cook kada dobije NFS podršku.

GPL verzije izlaze jednu verziju kasnije od supported verzine i cijena za jedan cluster je $5000 (za cluster ne za node!). Sve u svemu distribuirani filesystem koji obećava.

Well, it seems that Microsoft has a search engine. Let's see how good it works. Well, I entered dobrica as a search word expecting to find me and oh, err... Dobrica Cosic or other Dobricas which have web presence. But, what did I get? No search results. Strange.

Still in good faith, I tried something different: dobrica pavlinusic (yes, yes, I know: it shouldn't return result either). But, what did I get?

Search Error

MSN Search is temporarily unable to process your request.

Please try again in a few minutes.

EID: f:651496928 - 1041:1041:10004:1059

HC: 71d61b15

Od zadnjeg USENIX-a su napravili 9grid. Plan 9 i dalje radi na clusteringu, ove godine se očekuje port na 64bitnu arhitekturu. Plan je portati Plan 9 na Xen virtualne mašinu da bi plan9 radio na svim mašinama na kojima se vrti i Linux.

Jedan od većih problema (barem za IBM-ere) je što nije pod GPL licencom. Naime, u IBM-u je teško napraviti bilo što pod nekom od licenci koji su slobodne, a kako plan9 nema GPL licencu nego BSD, to im je problem.

Najveći zločinci Plan 9-a je naravno AT&T i poslije toga Lucent koji su htjeli ne ponoviti grešku sa Unix-om koji su dali svima pa su napravili obrnuto: Plan 9 nisu dali nikome.

Nakon jedno sat vremena došli su i Rob Pike i Dave Presotto (i sjeli točno pored mene :-) ali su uspjeli otići prije kraja. Iako sam i prije čitao u Plan 9 ipak je praktična demonstracija sa nekim tko ti može pokazati kako to radi nešto sasvim drugo. Dva sata kasnije (dok ovo pišem) mogu zaključiti samo da je velika šteta što Plan 9 jednostavno nije zamjenio Unix i što danas prevladava Linux a ne Plan 9 (za one koji koriste Windows i čitaju ovo: kročite u 1970! Samo pogledajte Plan 9 -- to je OS transparentan na mrežu! Dobro? Ne moramo više razgovarati o Windowsima, zar ne?)

Update: Shvatio sam da se gornja rečenica može shvatiti kao bashing, pa ću malo pojasniti (jer sam disableao komentare koji i tako i tako ne rade :-)
Dakle, zamislite da je sve file. I TCP stack i procesor. Dakle, imate Plan 9 na svom laptopu i vrtite nešto što vam je sporo. Ništa lakše, na drugoj strani mreže (bilo gdje!) imate prekrasan vrlo brzi CPU server X. Importate CPU sa njega i puf! Vaš program se vrti tamo. Potpuno transparentno. Imate firewall na Plan 9 i želite izaći negdje van. Importate TCP stack sa firewall-a i vaše konekcije idu sa njega. VPN? Importate TCP stack sa mašine koja je na drugom kraju mreže! Da, sve je enkriptirano i sigurno!! Želite pročitati mail sa mašine koja je u hrvatskoj? Importate svoj /lib/mail na laptop koji je bilo gdje. OK? Na to sam mislio!!

Google je ove godine imao zakusku, i uspio sam (umjesto majice, sorry!) dobiti gmail account! Cool. Siguran sam da će Mail::Box Web Search (sjećate se onog projekta za pretraživanje mailbox-a?) profitirati od toga!