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Messages - Mark0 [ switch to compact view ]

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Living Room / Re: Does anyone here use Bitcoins?
« on: March 12, 2018, 08:31 AM »

Crypto currencies: everything you don't understand about money, combined with everything you don't understand about computers!
-John Oliver

Notice this just now. Very nice find, thanks! Will surely recommend it to some friends.

Living Room / Re: Does anyone here use Bitcoins?
« on: July 13, 2017, 05:01 AM »
On the subject, fresh from EEVblog:

Pavol Rusnak, SatoshiLabs CTO, also posted on the forum to clarify some points:
EEVblog Electronics Community Forum - EEVblog #1006 - Trezor Bitcoin Hardware Wallet Teardown

Another leading HW wallet manufacturers is the french Ledger.

A HW wallet is surely highly recommended for anyone with a non trivial sum in cryptos, IMHO.

I have designed another related tool, that can both cover other scenarios and integrate with SeqBox:


The purpose of BlockHashLoc is to enable the recovery of files after total loss of File System structure, or without even knowing what FS was used in the first place.

The way it can recover a given file is by keeping a (small) parallel BHL file with a list of crypto-hashes of all the blocks (of selectable size) that compose it. So it's then possible to read blocks from a disk image/volume, calculate their hashes, compare them with the saved ones and rebuild the original file.

With adequately sized blocks (512 bytes, 4KB, etc. depending on the media and File System), this let one recover a file regardless of the FS used, or the FS integrity, or the fragmentation level.

This project is related to SeqBox. The main differences are:

  • SeqBox create a stand-alone file container with the above listed recovery characteristics.
  • BHL realize the same effect with a (small) parallel file, that can be stored separately (in other media, or in the cloud), or along the original as a SeqBox file (so that it can be recovered too, as the first step), so it can be used to add a degree of recoverability to existing files.

A nice practical demonstration of the level of optimiziations and features of moderns C++ compilers:

Living Room / The backfire effect
« on: May 03, 2017, 01:31 PM »

Living Room / Re: Recommend some music videos to me!
« on: April 27, 2017, 02:15 PM »
Sharon den Adel (Within Temptation) and Anneke van Giersbergen (The Gathering):

@Mark0: Thanks. The version 3 is necessary only because that is the version my daughter is being taught with at school.

I understand but usually, in the context of Python, when one say Python 3(.x) is to contrast that to Python 2(.x). At some point they decided to sort out the language, and loose some inconsistencies and ugliness even if the price was backward compatibility. So they have become like 2 different dialects, and you see all the time in Python projects stated that they'll work in Python 2 or 3 (and sometimes both).
So it's probably worth checking, but I doubt they are really using such an old version like 3.0.x.

The 3.0 version is quite old (years). The current one is 3.6.x:

As for 32 or 64 bit, it doesn't do much difference, except when dealing with some additional/external modules, but even those at this time are usually available in both versions. Basically you can't go very wrong either.

I saw often recommended "How to Think Like a Computer Scientist". You can find online both PDF and online/interactive version, like this one:

I liked a lot this Google Python Class by Nick Parlante, in 6 parts:

IMHO it's very well conducted and engaging, and can bring one up to speed and coding something interesting in Python very fast. The only con is that it's based on Python 2.x. But the difference in the topic explored aren't that great (mostly just put parenthesis after print, which is a function in Py3 and a statement in Py2).

Living Room / Re: Interesting "stuff"
« on: April 06, 2017, 07:29 AM »

but this really does sound like something everyone SHOULD be using

Well, I don't think we are quite there at the moment! :)
Let's say that, aside from experimenting, it could surely be used as additional back up/security measure.

Being a suite of command line tools it's not super user friendly, but I hope to add additional documentation and examples soon.

You could consider an SBX archive like a ZIP one, with only 1 file inside, and stored / non-compressed.
So yes, the file will need to be decoded / extracted with SBXDec to get the original file.
But, like there are software that can access files inside a ZIP archive without extracting it (like music players that directly can play MP3s stored inside a compressed archive), nothing prohibits to do the same with SBX archives.
It would be actually very easy, since the format is very simple, and the original file isn't changed in any way, just divided in blocks. As such even random access is possible without any issues.

Updated to v1.0.0.
Recovery tests have been done in various configurations:


Seqbox recoverability have been practically tested with a number of File Systems. The procedure involved using a Virtual Machine to format a small (about 100MB) disk image with a certain FS, filling it with a number of small files, then deleting some randomly to free enough space to copy a serie of SBX files. This way every SBX file results fragmented in a lot of smaller pieces. Then the image was quick-formatted, wipefs-ed and the VM shutdown.
After that, from the host OS, recovery of the SBX files was attempted using SBXScan & SBXReco on the disk image. 

  • Working: BeFS, BTRFS, EXT2/3/4, FATnn/VFAT/exFAT, AFFS, HFS+, JFS, MINIX FS, NTFS, ProDOS, ReiserFS, XFS, ZFS.
  • Not working: OFS (due to 488 bytes blocks)

Being written in Python 3, SeqBox tools are naturally multi-platform and have been tested successfully on various versions of Windows, on some Linux distros either on x86 or ARM, and on Android (via QPython). No test was done on OS X but it should works there as well (feedback welcome).

If someone can try it on a Mac (maybe with the new APFS), it will be much appreciated.  :Thmbsup:

I have updated the readme adding a sort of guide tour / demo to illustrate how the tools can be used:

Pretty nightmarish! Now on to SBXScan to search for pieces of SBX files around, and SBXReco to get a report of the collected data:

How is that for a fragmented floppy image?  ;D


A SeqBox container have a blocksize sub/equal to that of a sector, so can survive any level of fragmentation. Each block have a minimal header that include a unique file identifier, block sequence number, checksum, version. Additional, non critical info/metadata are contained in block 0 (like name, file size, crypto-hash, other attributes, etc.).

If disaster strikes, recovery can be performed simply scanning a volume/image, reading sector sized slices and checking blocks signatures and then CRCs to detect valid SBX blocks. Then the blocks can be grouped by UIDs, sorted by sequence number and reassembled to form the original SeqBox containers.

Tools are in Python 3.x, so they should work just about anywhere. I tried on a server with Linux, Win 10 PC, Raspberry Pi, Android.

Living Room / Re: Does anyone here use Bitcoins?
« on: March 06, 2017, 10:41 AM »
Anyone happy with the new ATH?

Surely not "Prof. Bitcorn"! :D

Set up a 21 profile to receive paid messages from people outside your network. Keep the money, or donate it to charities like Black Girls Code.
It's like LinkedIn InMail, except you get paid!

An interesting experiment...
I found about it when, just overnight, I started to see tweets by various notable (and non) people that activated an account. I have seen asking prices from 1$ to over 100$.

Will it gain some traction or be just a passing fad?
Don't know, but the idea to reach some otherwise unreachable person may have some appeal. Surely it works as an anti-spam! :)

Living Room / Re: The Keybase Filesystem
« on: February 09, 2017, 09:48 AM »
Interesting new development:

Introducing Keybase Chat
It's bigger than your address book

At Keybase we collectively use and love WhatsApp, Signal, Slack, and iMessage, to name a few. However, in all those apps: recipients are looked up by phone number or email.
That works ok with friends and coworkers.
But it sucks with people you know on the Internet. First off, they have to give you their phone number in a preliminary back and forth. That takes time and prevents you from sending your message until you hear back.
Then, to make sure you're really secure, you're supposed to compare special codes by meeting in person. That's impossible in most cases.
Keybase is different. For example, in Keybase chat, I can simply use my Hacker News name, malgorithms, as my secure address; no phone number or email needed. My Twitter username would work, too. Or even my Reddit username.

Interesting presentation, and memories!  ;D

At GDC 2016, Provinciano elaborated on exactly how he did it, and in the process shed light on how he reduced memory usage down to 4MB, increased performance to run on a 486 PC, reduced disk space to fit on a single 1.44MB floppy, and finally ported the game to MS-DOS itself.


The other video/talks referenced in the video are also interesting.

Yes, sorry.
I started posted thinking that the description of the process was the most interesting thing. Then realized that the emulator was indeed already in an advanced phase and so posted the video too, but totally forgot about the official website.  :D

Saw this series of articles mentioned on OSNews. Fascinating read indeed.

Why I’m writing a Windows 3 Emulator
I’ve decided to write a 16-bit Windows emulator. It’s a bit of crazy idea, but hear me out…


  • It’s like DosBox in that it’s emulating the CPU — but unlike DosBox in that it’s not emulating other low level hardware.
  • It’s like Wine in that it’s emulating the Windows API — but unlike Wine in that the CPU is emulated instead of running on a physical processor (remember Wine stands for “Wine Is Not an Emulator”).
  • It’s not like VirtualBox or VMWare or other virtualization software as it’s not emulating or virtualizing low level hardware.

Living Room / Re: External 5.25 floppy usb drive or another way?
« on: September 22, 2016, 04:53 AM »
Maybe you could make up a web page for it, with executables, documentation, etc.

BTW, Jimmy Maher has written a lot about Interactive Fiction: it may bring back some memories! :)

A great saving of space from newer archivers come from the so called "solid" mode: basically each file is processed after another as if it was a single  big stream, so that it's possible to exploit similarities among different files.
Probably the first widely used solid compressor in the DOS/Windows world was RAR. The same results can be obtained creating first a non compressed archive of the files, and the compressing the result (like the usual tar+gzip). Of course the compressor need to support windows of adequate size.

In the case of many PDFs with the same document in different languages, that means that a solid archiver can probably identify the pictures as the same blobs of data, so that they will be stored only one time.

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