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dfox

5,985 karma · joined April 28, 2008

http://hakl.net/ ales@hakl.net

[ my public key: https://keybase.io/adh; my proof: https://keybase.io/adh/sigs/-nlOT3TEcphUI1F_WEG_MzCvPXi5fQ6Z5oZaDLQGuVw ]

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dfox··on I spent a year making an ASN.1 compiler in D
It is not only that ASN.1 was there before SSL, but even the certificate format was there before SSL. The certificate format comes from X.500, which is the "DAP" part of "LDAP", L as in "Lightweight" in "LDAP" refers mostly to LDAP not using public key certificates for client authentication in contrast to X.500 [1]. Bunch of other related stuff comes from RSA's PKCS series specifications, which also mostly use ASN.1.

1] the somewhat ironic part is that when it was discovered that using just passwords for authentication is not enough, the so called "lighweight" LDAP got arguably more complex that X.500. Same thing happened to SNMP (another IETF protocol using ASN.1) being "Simple" for similar reasons.

dfox··on Die shots of as many CPUs and other interesting chips as possible
Mostly no. You do not see the lower layers and for anything sub 1um or so the resolution is too poor anyway.
dfox··on Burnend alive inside a Tesla as rescuers fail to open the car's door
The reasoning behind the auto-locking feature is that when the doors are locked it adds to rigidity of the car and thus decreases the likelyhood of the passanger cabin collapsing on the occupants. Auto unlocking the doors would completely defeat the reason for that feature.

The actual mechanism of how the door works as kind of "configurable deformation zone" usually involves somewhat thick steel rod running down the middle of the door that on hinge side abbuts similar strength member in the chasis and on the latch side connects to the latch. The latch has two distinct positions depending on whether the door is just latched or locked and the only latched position is not strong enough to hold the potential impact forces..

dfox··on Is OOXML Artifically Complex?
> The specifications document was so long that it would be difficult for anyone else to implement it properly.

In contrast to ODF specification that is long, complex and written in such a terse way that it really does only specify what is a valid ODF file and not in any way what it means. Good luck implementing that without just copying whatever LibreOffice does.

dfox··on With AI Boom, Dell's Datacenter Biz Is Finally Bigger Than Its PC Biz
My experience with Dell is that they are not that focused on selling enterprise support (at least compared to HPE), at most they will push for bundling hardware (cables, cable trays, front covers, PERC...) that you do not really need in order to get better volume discount.

Price-wise I don't see a meaningful difference between Dell and SuperMicro (or even "non-traditional" server vendors like Asus and Gigabyte).

dfox··on The day Return became Enter (2023)
Modern protocols running over RS-485 UART usually use some kind of HDLC-inspired framing scheme with flag characters and byte stuffing.

But still there is a lot of stuff that uses ASCII STX/ETX and then some kind of field separators inside otherwise human readable message. Things like industrial scales, industrial barcode readers and what not usually use something like that as default output format.

dfox··on The day Return became Enter (2023)
That is not an overloading, that is just preserving the behavior of Tab on IBM terminals.
dfox··on F-35 pilot held 50-minute airborne conference call with engineers before crash
The mishap involves doing touch-and-go twice with an arrested landing capable version of the aircraft. The report even says that they considered doing arrested landing, but it was deemed as too much risk for the pilot (apparently the actual flight manual of F-35A advises against trying that with non-centered NLG), because the ways how that could go horribly wrong do not allow for safe ejection.
dfox··on F-35 pilot held 50-minute airborne conference call with engineers before crash
The article is somewhat sensationalistic. If you read the actual report you will find out that:

The pilot was not part of the conference call!

What froze was not hydraulic fluid for actuators (in some hydraulic line), but hydraulic fluid in the shock absorbers.

The last paragraph of the article and seems to be missing a few words and reads as the investigators blaming the people directly involved, which is essentially a complete opposite of what conclusions of the report say.

dfox··on F-35 pilot held 50-minute airborne conference call with engineers before crash
The actual report mentions that this was a concern for actually landing the plane (as opposed to touch and go), because there was real possibility that the plane would end up in attitude that can hardly be described as "roughly level".
dfox··on In 2006, Hitachi developed a 0.15mm-sized RFID chip
If you want the bare chips and not full assembled labels the usual packaging is uncut wafer and cutting out and handling the individual dies is your problem.
dfox··on In 2006, Hitachi developed a 0.15mm-sized RFID chip
I did work with that recently. Did a few cool demos.

The tags got cheaper and you can even get tags that are intentionally designed for metal surfaces. Unlike NFC (or barcodes, obviously), you can read hundreds of tags essentially simultaneously. But because the reading is far from being perfectly reliable (one thing we found out is that human body blocks the 868MHz RFID completely, even at something like 50dBm EIRP, which is well above what is considered safe for human presence) the applications are indeed somewhat limited.

But apparently there are two classes of applications where this technology is really common: libraries and bulk checkout at sports equipment retailers (seems oddly specific). Both of these things also benefit from the "advanced" features of UHF RFID tags like dual-mode RFID/EAS tags and ability to permanently deactivate the tag by simple command.

dfox··on It's a DE9, not a DB9 (but we know what you mean)
Coax and high-current/voltage pins are not that weird. You can also get truly weird semi-proprietary pins like fiber optics or even pneumatics/fluidics.
dfox··on It's a DE9, not a DB9 (but we know what you mean)
IBM did that pretty often. And well, the original VGA connector had pin 9 missing and used as a key.
dfox··on ESIM Security
It is my understanding that Starlink does not do home-grown crypto of the 3GPP-kind. Also because it is closed ecosystem there is no need for SIMs and the associated deployment mechanisms.
dfox··on Reflections on 2 years of CPython's JIT Compiler
Ruby in both its semantics and implementation is very close to smalltalk and does not really use the Python's object model that can be summarized as "everything is a dict with string keys". That makes all the tricks discovered over last 40 years of how to make Smalltalk and Lisp fast much more directly applicable in Ruby.
dfox··on The X Window System didn't immediately have X terminals
The one I still probably have somewhere has PowerPC and S3 video card.
dfox··on The X Window System didn't immediately have X terminals
As for NCD X terminals (at least the later ones), surprising amount of stuff could run directly on the terminal (which ran some weird MMU-less BSD variant): mwm and motif session manager, dtterm-like terminal with telnet and serial port support, some kind of JVM and two different variants of mosaic were part of the SW package (it booted either from flash PC card or from NFS).
dfox··on CPU-Based Layout Design for Picker-to-Parts Pallet Warehouses
This is not particularly novel. Essentially any large-ish retail warehouse I have been in uses some kind of layout similar to their "CPU-based layout". And I have seen warehouses that were not explicitly designed like that, but this kind of layout came up somewhat organically.
dfox··on The Windows Subsystem for Linux is now open source
The original POSIX subsystem was just there so MS could say that it exists (and pass DoD requirements).

It got actually somewhat usable with the 2k/XP version, slightly better in Vista (notably: the utilities installer had option to use bash a default shell) and IIRC with 7 MS even again mentioned existence of the thing in marketing (with some cool new name for the thing).

dfox··on Blog hosted on a Nintendo Wii
Working from the fact that the NetBSD sees the OHCI controllers which are on the Starlet's AHB this runs with AHBPROT disabled (as does most homebrew), so NetBSD can in theory not only interact with Starlet mailboxes (as any normal game), but can also do pretty much anything to it as the entire Starlet address space is R/W accessible from Broadway (which on the other hand makes interacting with Starlet pretty much irelevant for normal use, as you can interact with the hardware directly using normal drivers instead of going through IOS)
dfox··on Behind the 6-digit code: Building HOTP and TOTP from scratch
Doing similar idea with asymetric cryptography is problematic due to the size of messages involved that are not exactly convenient to type. Lower bound for the signature size is going to be something on the order of 128bits if we include "weird" signature algorithms (ie. string that looks like MS Product Key), 240b for Schnorr with safe-ish parameters, at least 512b for anything widely accepted.

You can probably come up with something related to S/KEY (which was kind of a precursor to HOTP) that can be made to work with arbitrary sized one time passwords and is technically asymetric (and quantum resistant at that), but the security trade-offs involved in that and somewhat wild user registration step of S/KEY make HOTP/TOTP more sane choice.

dfox··on Behind the 6-digit code: Building HOTP and TOTP from scratch
And many actual implementations work the other way around. Which opens the user to credential compromise but is much better user experience (and only one possible with several kinds of hardware tokens).
dfox··on Remember FastCGI? (2021)
In my opinion that was step in the right direction, but the protocol design is truly weird. Somehow managing to come up with 4 different ways to encode length of byte strings in otherwise so simple protocol is remarkable achievement.
dfox··on Writing C for Curl
> https://github.com/curl/curl/blob/master/lib/vquic/vquic.c

When somebody says "short identifiers" in relation to C, this is exactly the style meant by that, not the cryptic style of C standard library.

dfox··on Actually drawing some ovals – that are not ellipses (2017)
Interesting contrast to this is that most modern vector 2D graphics API use PostScript/PDF drawing model that cannot represent exact circles and elipses and these are instead interpolated by a bunch of bezier curve segments.
dfox··on Actually drawing some ovals – that are not ellipses (2017)
If you want the resulting geometry to be precise you are pretty much limited to equivalent of compass and straightedge (or well, in mechanical engineering lathe and mill, which are basically the same things). if you start somehow calculating the geometry you are limited by precision of the calculation, but more importantly by precision of measuring distances you can achieve.
dfox··on Things I Won't Work With: Dioxygen Difluoride (2010)
These are mixtures of fluorine and oxygen, not FOOF.
dfox··on Blue95: a desktop for your childhood home's computer room
Another issue with modern recreations of old UIs is that the dimensions are usually subtly wrong, which for me ruins the feeling. Some of that is related to the fonts having different height, but in many cases it is just that something is one-pixel off and just looks wrong. For the 95-style UI the common issue are control borders (especially the high-light side of "3d" controls), of which there is a huge amount of examples on the screenshot.
dfox··on A note on the USB-to-PS/2 mouse adapter that came with Microsoft mouse devices
There is a difference between DP+ and DP++. DP+ uses external level shifter, DP++ uses passive adapter and the card switches different transmitter into the path internally.
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