Back in university, my friends and I had a trick when it came to exams in advanced physics and math courses: we’d try to sit exams with a postdoc or, better yet, a PhD student rather than a seasoned professor. Professors, with decades of experience, could gauge a student’s depth of understanding after just a few questions, accurately assigning grades. PhD students, however, lacked this refined intuition and often gave higher grades if you could converse confidently about basic concepts and demonstrate a good grasp of basic terminology. They usually tended to assume the best, consciously or subconsciously. The real test wasn’t the material itself, but skilfully steering the exam into a dialogue where you could shine.

So, why do I find myself reflecting on this old trick now? ( Read more... )

I just lost several hours today debugging the following:

I am linking to a library that has a function declared in a header as:
MACRO_EXPANDING_TO_RETURN_TYPE create_object_pointer(uint64_t* arg1, int arg2, int arg3);

I can’t include the corresponding header, so just cut&pasted the function declaration before use as:
extern
MACRO_EXPANDING_TO_RETURN_TYPE create_object_pointer(uint64_t* arg1, int arg2, int arg3);

Then I was calling it in my code:
return another_lib_func (create_object_pointer(arg1, arg2, arg3), “PASSING RESULT FROM lib_func");

another_lib_func is:
int another_lib_func(RETURN_TYPE t, String s)
{
If (t == NULL) return -1;
If (t->value < 0) return -1;
….
}

It segfaulted in another_lib_func, at second line. Why?
( Read more... )

Is it a good time to move?

Regardless, with current regulations we should fly within 4 weeks. See you there soon!

20 years ago I started working for Nortel as a contractor. One of my first assignments was to write a script in C to automatically stress test creating tons of entries in a pre-SQL database (developed in 70s) that was storing cellular network configs.

The database mixed data with code processing it, so each config had to be tested separately. The config I had to test was lawful intercept config. For every cell phone number that could be eavesdropped on, there should have been an agency name string and court order/secret order number attached.

So I added MI6 with secret order numbers beginning with 007, and KGB with secret order numbers beginning with 1937, and ran tests where most of cell subscribers were being listened to by KGB.

Few years ago I managed to attend both MWC and Embedded world. Now no more MWC :(, and Embedded world looks half empty.

All NDAs have expired, so I can start a diary with 20 years delay.

I started working as a full time software engineer in November 1999. The product I was working on was supposed to be a VOIP phone, to be shown at CeBIT 2000. The hardware platform was set and ready, with Motorola Dragonball CPU and a DSP (I dont recall the make). In the team there were three programmers working on VOIP software, two system software engineers including myself, and a contractor who developed DSP API and driver.

During 9 months I was working on that little thing, I hacked GCC backend to produce correct code for uCLinux/Dragonball (first C, then C++ with exceptions support), implemented a watchdog, created an app to configure the phone's IP settings with DTMFs, and fixed couple of bugs in DSP driver.

I have a lot of respect for the Mera management, who invested a lot of money to this product development, and although it was not commercial success, some bits from this project ended up in other more successful products. Alas these bits that survived were not platform related, so all my work had quickly perished.

It was a great experience: I could use unlimited internet at work, and some times I stayed there at night. The team was great and I am still in touch with two of my teammates (both moved to US).

My salary was $200 first, quickly raised to $300. (That was a lot of money for a student in Nizhny Novgorod, 1999/2000). E.g renting a good one bedroom apartment was ~$100.

1988 - Moldavian make.
1990 - Spectrum'48 clone, assembled at a local avionics factory.
1992 - Spectrum'48 with proper keyboard and monitor, 5'' floppy drive and AY38910-12
1995 - Intel 80286, 1MB RAM, 270MB!!!HDD, DOS 6.22
1996 - 2400b modem upgrade => 2:5066/44.0 - FIDONET!
1997 - AMD K5 100Mhz, 8MB RAM, still 270MB HDD, CDROM, Win95OSR2
Moved to Nizhny Novgorod
1998 - 80486, 4MB RAM, Linux Slackware/1.2 kernel
2001 - Pentium 4, 16MB RAM, Win2k/Linux Slackware 2.2 kernel
2002 - iBook clamshell, MacOS X
Moved to St. Petersburg
2004 - Mac Mini
...
Now I have many Macs to play with :)

Starting today, I no longer work at Intel. That were great 16+ years, but now it is time for a change. My new job is even more interesting, but I am not going to post anything about it online. Just one thing: my job title has changed from Application Engineer to S/w Performance Engineer.

Every time I suspect I found a CPU errata, it ends up being something else. This time a compiler bug, again.
GCC 8.2.1, compiles _mm512_*fmaddsub*_pd intrinsics to vfmadd132pd instruction when compiling with -O0.

When compiling with -O1, -O2 or -O3 it compiles to vfmaddsub132pd, as expected. Happy debugging!

Big data, AI.. Look at a screenshot from one of the biggest US job sites:

:)