The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘History’ Category

2018 Hard Drive Reliability Stats by Manufacturer and Model

Posted by jpluimers on 2019/02/11

We look at the hard drive failure rates for the data drive models in operation in our data centers in 2018 (now totaling over 750 petabytes and 100,000 drives). In addition, we’ll see how the new hard drive models we added during the year did, including our 12 TB HGST and 14 TB Toshiba drives.

Full article: [WayBack] 2018 Hard Drive Reliability Stats by Manufacturer and Model

Statistical data at [WayBack] Backblaze Hard Drive Stats:  Hard Drive test data from the Backblaze data center. Backblaze is affordable, easy-to-use cloud storage.

Via [WayBack] 2018 Hard Drive Reliability Stats by Manufacturer and Model https://www.backblaze.com/blog/hard-drive-stats-for-2018/ – DoorToDoorGeek “Stephen McLaughlin” – Google+

–jeroen

Posted in Backup, Hardware, History, LifeHacker, Power User, Storage | Leave a Comment »

Di Cleverly – Google+: on 42 and geek stuff

Posted by jpluimers on 2019/02/11

Since it is the 42th day of this year: Via [WayBack] Di Cleverly – Google+

  • Adrian Colley
    For a slightly more serious answer, asterisk is most commonly used (in computing) to mean “repeat the previous pattern zero or more times”. In HHGttG, it’s suggested that if the Question and the Answer were known at the same time, the universe would vanish and be replaced by something even more bizarre and inexplicable. There is a theory that this has happened several times. Zero or more times, you might say.
  • pedant powers activated !

    in regex * is zero or more of the preceding character, but there is no preceding character

    as a file glob * is zero or more anything

    as an operator * is multiplication, but there are no operands

    in sports * next to a stat flags possible cheating

    there will be others if I go looking, but I think the point is that the question was ill defined with lack of context, therefore the answer is also ill defined with lack of context, at least that is how I interpreted the answer when I first saw the tv series (it was a radio show before that, but I never heard it)

    saying the answer is * is also ill defined and lacks context (i.e. is * a regex or a glob or an operator or …)

    also ASCII is not computer software, let alone the most basic computer software, ASCII is simply an agreed mapping from numbers to symbols eg 01000001 = 65 = 0x41 = A

    so if 42 was actually hexadecimal, then 42 = B and maybe the question was multi-choice (aka multi-guess), therefore my answer is 44 = D = all of the above

  • +Perry Winkle not ever regular expression. And as i said the books predates regex.
  • +Martin Krischik in sed, vi, awk, Perl, Python, Posix and many others it is, any exceptions would be painful regex engines to work with IMO

    also, I think you’ll find regex is actually older than HHGttG. HHGttG was first a radio play in 1978, regex was coined in the early 1950s for algebra and used in unix in the early 1970s

  • Jeroen Wiert Pluimers

    Sorry to spoil it: groups.google.com – Why 42 ? where in 1993, Douglas Adams writes:

    <<
    The answer to this is very simple. It was a joke. It had to be a number, an
    ordinary, smallish number, and I chose that one. Binary representations,
    base thirteen, Tibetan monks are all complete nonsense. I sat at my desk,
    stared into the garden and thought ’42 will do’ I typed it out. End of story.

    Best,

    Douglas Adams
    London, UK | d…@dadams.demon.co.uk (dormant)
    Currently in Santa Fe, NM | ada…@nic.cerf.net (current)
    >>

  • The first time someone handed me an iPhone with Siri, I asked the meaning of life, the universe, and everything. Siri simply gave me information on those specific search terms. (More recently I asked the question again, and Siri answered 42)

    Google responded with a reference to Bill & Ted’s Excellent Adventure, “Be excellent to each other”.

    I need someone to ask Alexa and report back.

    I’m using this to gauge where we are in the possibility of having AI overthrow humanity in the immediate future. 😁

  • Di Cleverly
    +Martin Krischik he played the guitar left handed! Wow! You really do learn something new everyday!
  • +Adrian Colley You’re mixing regex with “everything in computing”

    +Martin Krischik And Douglas Adams worked mainly with Apple and Unix. Apple ripped off the * wildcard from Unix, CPM ripped it off from Apple, and MS-Dos ripped it off from CPM. The fact that DOS used it isn’t relevant. And regex started in 1951. A quick Google search confirmed that. So yes, it was in existence in 1979. GREP was using regex long before 1979. And yes, DA’s programming experience would have exposed him to all this. You seem to be conflating degrees with actual ability.

  • Perry Winkle (Shy Geek)

    FYI (geek alert) Unix was popular as a document printing/typesetting system early on hence tools like latex and nroff/troff (especially for printing formulas in computer science papers etc)

    (trivia alert) grep comes from the ed (or sed) command g/re/p where re is short for regular expression, it translates kind of as “globally in the file/stream, if the re matches, then print the line”

–jeroen

Read the rest of this entry »

Posted in Fun, History | Leave a Comment »

6502 emulation: the ICE, or in-circuit-emulator…

Posted by jpluimers on 2019/02/05

On my list of hardware things to try:

[WayBack] a different take on 6502 emulation: the ICE, or in-circuit-emulator… – mos6502 – Google+

Basically it consists of three parts:

 

–jeroen

 

Posted in 6502, Development, Hardware Development, History, Z80 | Leave a Comment »

Fast inverse square root – Wikipedia

Posted by jpluimers on 2019/01/24

Cult code via [WayBack] Fast inverse square root – Wikipedia part of [WayBack] Quake-III-Arena/blob/master/code/game/q_math.c:

float Q_rsqrt( float number )
{
    long i;
    float x2, y;
    const float threehalfs = 1.5F;

    x2 = number * 0.5F;
    y  = number;
    i  = * ( long * ) &y;                       // evil floating point bit level hacking
    i  = 0x5f3759df - ( i >> 1 );               // what the fuck? 
    y  = * ( float * ) &i;
    y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
// y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

    return y;
}

It is a really fast way to approximate the square root for 32-bit IEEE754 calculations having origins around 1986:

  • [WayBackSymplectic Spacewar » Cleve’s Corner: Cleve Moler on Mathematics and Computing:

    Cleve Moler replied on June 27th, 2012 9:35 pm UTC :

    Jotaf — Thanks very much for your comment, and for reminding me about the fast inverse square root hack. I didn’t realize that the trick had attained a kind of cult status in the graphics community. The trick uses bit-fiddling integer operations on a floating point number to get a good starting approximation for Newton’s iteration. The Wikipedia article that you link to describes the trick in great detail, and also links to an article by Rys Sommefeldt about its origins. Sommefeldt goes back to the late ’80s and to me and my colleague Greg Walsh at Ardent Computer. I actually learned about trick from code written by Velvel Kahan and K.C. Ng at Berkeley around 1986. Here is a link to their description, in comments at the end of the fdlibm code for sqrt. http://www.netlib.org/fdlibm/e_sqrt.c . — Cleve

  • [WayBack] http://www.netlib.org/fdlibm/e_sqrt.c 

By now there is also a constant for 64-bit IEEE754 calculations 0x5fe6ec85e7de30da by [WayBack] 2003 research from Chris Lomont who also found a better 32-bit constant 0x5f375a86.

Note you need to be careful with boundary values like zero and infinity. This holds for approximations in general: [WayBackperformance – Why is SSE scalar sqrt(x) slower than rsqrt(x) * x? – Stack Overflow

–jeroen

Posted in Algorithms, C, Development, History, Software Development | Leave a Comment »

TED Talks on Twitter: “The real reason female entrepreneurs get less funding: @KanzeDana… they get asked different questions than male ones”

Posted by jpluimers on 2018/12/26

Interesting watch: [WayBack] TED Talks on Twitter: “The real reason female entrepreneurs get less funding: @KanzeDana… “

Via: [WayBack] The real reason female entrepreneurs get less funding … Gender gap in startup funding: Dana Kanze and collaborators found a surprising… – Marjan Venema – Google+

Gender gap in startup funding: Dana Kanze and collaborators found a surprising, consistent trend: in meetings with funders, men and women were being asked completely different types of questions.

Video at [Archive.is/WayBackDana Kanze: The real reason female entrepreneurs get less funding | TED Talk

 

–jeroen

Posted in Awareness, History | Leave a Comment »

 
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