Cache and carry
p2pnet news view | P2P | Music:- “I was listening to a CBS [url="http://player.play.it/player/player.html?v=4.6.27&id=14596"]Flash Internet station[/url] in September,” writes long-time p2pnet mate Jack Spratt on p2p-zone.
“Something I’d been doing with my Opera browser since the summer. Just for kicks I opened the cache (C:\Documents and Settings\SprattsJ\Local Settings\Application Data\Opera\Opera\cache) and moved some files to another player,” he says, going on »»»
Not that I was expecting much
Until last year Opera`s cache included file endings (which looked something like opr088LY.xyz), making it simple to pull up pictures, mp3s, video files and games, but no more. By version 8 or 9 they had joined other browser makers and eliminated the endings, and what had been another in a long line of good reasons for using Opera as well. Now they’re just indeterminate files like opr088LY.
So when I dumped these mysterious little units into Winamp I didn’t think they’d play. But they did. Of the thousand files loaded into Winamp, seven hundred worked. When I put them into Media Player Classic, they all worked. Bit rates varied but they all sounded consistent and punchy, due probably to the Orban processing the station uses.
About 15 new files came in each hour I streamed the station. So I did, running it every day from 8 am till midnight, until the empty space on my drive filled with 6500 tracks. After analyzing them with a free duplicate-file eliminator this week I wound up with 2700 unique songs. Then I made a playlist and randomized it for variety. Verdict? Sounds just like the station. Identical actually, without the breaks or announcements.
Next I gave GrooveShark a spin. I saw a poll on the most beautiful songs at a bulletin board. A reader [url=http://listen.grooveshark.com/#/playlist/Most_Beautiful/18925773]streamed[/url] a few dozen submissions. I played it yesterday. When it ended I looked in the Opera cache and there they were, all thirty-nine of them. I moved them to a new folder called Most Beautiful and this is what I got:
opr016P5
opr016QY
opr016T8
opr016TC
opr016TI
opr016TN
opr016TS
opr016TV
opr016TZ
opr016U3
opr016UP
opr016V1
opr016V4
opr016V8
opr016VG
opr016VM
opr016VP
opr016VS
opr016VW
opr016VZ
opr016W4
opr016W9
opr016WB
opr016WG
opr016WK
opr016WP
opr016WT
opr016WX
opr016X0
opr016X2
opr016X6
opr016X8
opr016XD
opr016XH
opr016XK
opr016XP
opr016XS
opr016XW
opr016XZ
Pretty perplexing, right? But wait. I dragged them into my player, removed a few files I didn`t want, added a couple I did.
This is how Winamp then showed the very same file group:
1. Aphex Twin – Flim (2:53)
2. Beethoven – Moonlight Sonata (6:50)
3. Eva Cassidy – Over the Rainbow (4:59)
4. Jeff Buckley – Hallelujah (Grace) (6:55)
5. Pink Floyd – Wish You Were Here (5:34)
6. Sigur Rós – Starálfur (6:46)
7. Radiohead – Exit Music (For a Film) (4:24)
8. Beatles – In My Life (2:27)
9. Imogen Heap – Hide And Seek (4:28)
10. Debussy – Clair de lune (4:53)
11. New York Philharmonic;Leonard Bernstein – Adagio for Strings from the String Quartet, Op. 11 (Instrumental) (9:58)
12. The Smiths – There Is a Light That Never Goes Out (4:02)
13. Sufjan Stevens – John Wayne Gacy, Jr. (3:19)
14. Iron And Wine – Naked As We Came (2:32)
15. Moby – Porcelain (4:01)
16. Neutral Milk Hotel – In the Aeroplane Over the Sea (3:22)
17. Massive Attack – Teardrop (5:30)
18. Beethoven – 9Th Symphony (11:20)
19. Pink Floyd – The Great Gig in the Sky (4:44)
20. Flaming Lips – Do You Realize?? (3:32)
21. Neutral Milk Hotel – Oh Comely (8:18)
22. Sufjan Stevens – Casimir Pulaski Day (5:54)
23. Wilhelm Kempff – Piano Sonata #17 in D minor “The Tempest”, Op. 31 No. 2: 3. Allegretto (7:17)
24. Elliott Smith – Waltz #2 (XO) (4:40)
25. Okkervil River – Black (4:39)
26. Fleetwood Mac – Landslide (3:18)
27. Eva Cassidy – Fields of Gold (4:42)
28. The Beach Boys Caroline, No (2:17)
29. Radiohead – Everything in Its Right Place (4:11)
30. Erik Satie – Gnossienne no. 1 (3:49)
31. Fleet Foxes – Drops In The River (4:13)
32. Ludovico Einaudi – nuvole bianche (5:57)
33. Original Soundtrack – Halcyon and On and On (9:24)
34. Bjork – Unison (6:47)
35. Deutsche Opera Berlin – The Marriage Of Figaro: ‘duettino – Sull ‘aria’ (3:33)
36. Led Zeppelin – Stairway to Heaven (8:03)
37. Jonathan Edwards – Sometimes (2:47)
38. Delibes – Lakme (Flower Duet) (6:14)
Presto.
As you can see the ID3 tags survived the process and Winamp displayed them properly. Apparently as long as the stream had them it will.
I created a playlist and dropped it into MPC, merged it with the original 2700 song file and randomized it again. Simple.
“Finally I put the whole thing on a thumb drive and stuck it in a small laptop I carry around,” Jacksays, adding:
“Outside, in the car etc. It turned out to be a very easy way to clone my favorite station and free it from the net.”
heh. Good one, Jack. 
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(If you don`t fancy online payments, please email me at p2pnet @ shaw dot ca and I`ll send you my snail-mail address.)
First they ignore you, then they laugh at you, then they fight you, then you win ~ Mahatma Gandhi
p2p-zone – Volume VIII, Issue Number I, November, 2009
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November 30th, 2009 at 11:10 am
Files have no extension for a reason – to prevent users from wandering in the cache and opening files by double-clicking. Files in the cache can have malicious content and should not be opened just by double-clicking.
There is a MIME type served by server and there is a file association that is used to choose an application to open the file with. When the two do not match, we have e-mail viruses (e.g. file.exe marked as image/png, and Outlook Express running it as executable on preview).
Unfortunately, there is still “magic” guessing in MS file handling, e.g. try to rename your file.doc to just “file” with no extension and double-click it.
November 30th, 2009 at 12:02 pm
Shhhhhhhhhh! I’ve been keeping that on the downlow and for videos too!
November 30th, 2009 at 7:34 pm
That is one unnatural mix of wax. Like Roger Waters once said, “I can’t imagine anyone who would buy Englebert Humperdinck’s new record and the Cream’s.”
December 1st, 2009 at 1:37 am
“Until last year Opera’s cache included file endings (which looked something like opr088LY.xyz), making it simple to pull up pictures, mp3s, video files and games, but no more. By version 8 or 9 they had joined other browser makers and eliminated the endings, and what had been another in a long line of good reasons for using Opera as well. Now they’re just indeterminate files like opr088LY.
So when I dumped these mysterious little units into Winamp I didn’t think they’d play. But they did.”
Congratulations, you’ve just discovered that file extensions have absolutely no effect on the contents of a file.
Back in the early days of home computers (AKA before the dawn of recorded history for most of today’s users), computers didn’t have a GUI. There were no mice and no icons to click on. When you wanted to run a program, you typed in its name. Once it was loaded, if you wanted to open other files with it, such as pictures, you used the “Open File” option provided by the program and usually selected the file to be opened by using the arrow keys to move the selection bar to the file you wanted. Although there were some programs that insisted on files having the proper extension, for the most part, filename extensions existed to serve as a visual reminder of what each file was.
When GUI based OSs came along, the idea of double-clicking to open files was born. You could run programs by double-clicking them and you could open data files by double-clicking them. To do this, the OS looks at the extension, looks up that extension in its internal list, sees what program is “associated” with that extension, loads that program and passes the file to it. The OS doesn’t really know what the file is, it just relies on the extension. If the extension is wrong, the file will be passed to the wrong program. Since this can lead to crashes when a program tries to process random data, file “headers” were invented. A file’s header contains information that tells the program what type of file it is. If the program doesn’t recognize the header, it will probably refuse to open/play/display the file. In the case of audio/video files, the header contains information about the codecs needed to play the file.
If you use the same program to view JPG and GIF files, you can rename one to the other and they will still work, because both extensions are passed to the same program. On the other hand, if you rename a JPG file to TXT, Notepad or whatever program you use for a text editor isn’t going to know what to do with the file.
This also means that removing the extension in no way changes what the file is, it only eliminates the OS’s ability to automatically pass it to the apropriate program when you double-click it. If you were to rename a file from “Some-Song.mp3″ to “Some-Song”, you haven’t changed anything other than the filename. It’s still an MP3 file. If you drag & drop that file on your media player, or you use the Open option from the file menu, it’s going to look at the file’s header, see that’s an MP3 file and play it.
There’s nothing magical about file extensions, they’re simply a convenience feature that allows you to load files by double-clicking and which serves as an easy indicator or what the files are.
“Files have no extension for a reason – to prevent users from wandering in the cache and opening files by double-clicking. Files in the cache can have malicious content and should not be opened just by double-clicking.
There is a MIME type served by server and there is a file association that is used to choose an application to open the file with. When the two do not match, we have e-mail viruses (e.g. file.exe marked as image/png, and Outlook Express running it as executable on preview).”
Which is a perfect example of why people shouldn’t be using any of the software that Microsoft provides with Windows, not even the picture and fax viewer. Any piece of software that is broken enough to execute an EXE labelled as JPG, should be disabled and/or uninstalled immediately and replaced with something designed by someone who knew what they were doing.
I just renamed a harmless EXE file (a small game) to several popular extensions;
JPG – Irfanview opened and displayed the program’s icon.
RAR/ZIP – WinRAR & WinZip both told me it was a bad archive.
AVI – Media Player Classic told me that the video was in an unknown format.
HTML – Firefox showed me a raw listing of the file’s contents.
PDF – Foxit Reader failed to open at all.
TXT – Metapad told me that it wasn’t a text file, asked if I wanted to load it anyway and then displayed the raw file contents.
TORRENT – uTorrent told me it was an invalid file.
DOC – My Word viewer (I don’t have Word) told me it was a bad file.
PAR2 – Quickpar opened, but ignored the file.
SFV – Fsum opened then immediately closed.
I’m failing to see the danger here, especially considering that 99% of today’s users have no idea what a browser cache is, let alone how to actually find it on their system. Anyone with the expertise to find the files would hopefully be intelligent enough to be using software that doesn’t act like a universal file opening system that tries to figure out what each file is and open it regardless.
And I can’t help commenting on the sad state of today’s computer competency level, when the ability to find files on your hard drive needs to be classified as “expertise” rather than a basic skill that every computer user should have.