Category: Technology

I work in technology sector. And I do round a clock, not only from 9 to 5. It is my bread and butter, it is my hobby, it is the fascination of my life. And with the current rate of change particular in information technology (IT), there is always something new to learn, to try, to talk about. I often post news, thoughts, and reviews. And when I do, this is the category I use.

Five Linux-Ready, Cost-Effective Server Control Panels

webuzo

“Five Linux-Ready, Cost-Effective Server Control Panels” reviews 5 some alternatives to cPanel, which, they say, is rather expensive.  My beef with cPanel is not the price, but the technical merit.  Even though I love the fact that it is written in Perl, I don’t agree with its “let me handle everything” approach.

cPanel installs all the software that it helps to manage.  This might be a “so what” issue for most people, but not for me.  I like my servers clean.  And I want to utilize the tools that already come with my server – RPM, yum/dnf, etc.  Control panels can help with routine, but when something breaks, I should be able to go to the config files and deal with the problem using the distribution’s recommended ways.  cPanel, unfortunately, breaks that.  It downloads sources, applies patches, locally compiles things, and has its own layout for configuration files.  That’s too much mess for me.

I haven’t used any of the other control panels reviewed in the article (I usually prefer the command line way), but I hope they aren’t as intrusive and abusive as cPanel.  Sometimes control panels are useful for providing a bit of help to non-technical users (create mailbox, change email password, backup the website, etc), but if they are as needy as cPanel, thanks, but no thanks.

When monospace fonts aren’t: The Unicode character width nightmare

I don’t deal with Unicode and other character encoding on the daily basis, but when I do, I need every piece of information that has been written on the subject.  Hence the link to this interesting issue :

As long as you stick to precomposed Unicode characters, and Western scripts, things are relatively straightforward. Whether it’s A or Å, S or Š – so long as there are no combining marks, you can count a single Unicode code point as one character width. So the following works:

	aeioucsz
	áéíóúčšž

Nice and neat, right?

Unfortunately, problems appear with Asian characters. When displayed in monospace, many Asian characters occupy two character widths.

Replicant – fully free Android distribution

replicant-4.2-crespo-homescreen

Replicant is a fully free Android distribution running on several devices, a free software mobile operating system putting the emphasis on freedom and privacy/security.

Found via a mention in the Slashdot interview with Richard Stallman.

Latency Numbers Every Programmer Should Know

latency

I’m saving this here for current and future generations of programmers:

Latency Comparison Numbers
--------------------------
L1 cache reference                            0.5 ns
Branch mispredict                             5   ns
L2 cache reference                            7   ns             14x L1 cache
Mutex lock/unlock                            25   ns
Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000   ns
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms
Read 1 MB sequentially from memory      250,000   ns    0.25 ms
Round trip within same datacenter       500,000   ns    0.5  ms
Read 1 MB sequentially from SSD*      1,000,000   ns    1    ms  4X memory
Disk seek                            10,000,000   ns   10    ms  20x datacenter roundtrip
Read 1 MB sequentially from disk     20,000,000   ns   20    ms  80x memory, 20X SSD
Send packet CA->Netherlands->CA     150,000,000   ns  150    ms

Notes
-----
1 ns = 10-9 seconds
1 ms = 10-3 seconds
* Assuming ~1GB/sec SSD

Credit
------
By Jeff Dean:               http://research.google.com/people/jeff/
Originally by Peter Norvig: http://norvig.com/21-days.html#answers

Contributions
-------------
Some updates from:                      https://gist.github.com/2843375
Great 'humanized' comparison version:   https://gist.github.com/2843375
Visual comparison chart:                http://i.imgur.com/k0t1e.png
Nice animated presentation of the data: http://prezi.com/pdkvgys-r0y6/latency-numbers-for-programmers-web-development/

This is a copy-paste of this gist, referenced from this blog post. Read and share both, for the better world.