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Category: Computer Science

Threads vs. Watts

So I have been testing, again.

My hapless test subject this time is a Dell Box, an R630.

It has a comfortable 384GB of memory, one of two 25 GBit/s ports active, and it comes with two E5-2690v4 CPUs. That gives it 14 cores per die, 28 cores in total, or with hyperthreading, 56 threads.

$ cat /proc/cpuinfo | grep 'model name' | uniq -c
56 model name : Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz
$ ./mprime -v
Mersenne Prime Test Program: Linux64,Prime95,v28.10,build 1
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Symantec considers exiting the Certification business

Apparently, between being asked to behave responsibly by Google and the Certificate Transparency project, and LetsEncrypt eating into the profit margins in the Cert market in general, Symantec are reconsidering their presence in the CA market completely.

Reuters reports:

Cybersecurity firm Symantec Corp is considering selling its website certification business, in a deal that could fetch more than $1 billion and extricate it from a feud with Alphabet Inc’s  Google, people familiar with the matter said on Tuesday.

We remember that Symantec have proven themselves to be unable to run a CA properly earlier. The Reuters article also nicely reminds us which other toxic snake oil assets are still part of Symantec (i.e. Blue Coat) and which are possibly recovering after having been sold off (i.e. Veritas).

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Moving from 1Password to Enpass

In order to move customers from a “purchase a license” to a subscription model, AgileBits is experimenting with dropping support for local vaults, requiring cloud storage of passwords.

There is a lot of blowback in Blogs and the 1Password support forums. Also, the security professionals on Twitter frown on this, quite a bit (Thread).

Discussion on Facebook pointed to Enpass, and that is actually looking like a pretty good 1Password clone.

Enpass on Mac, Main Screen
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Using MySQL Partitions (a Python example)

Today somebody had a problem with expiring a large table (a Serendipity Blog table).

In MySQL InnoDB, tables are physically ordered by primary key (InnoDB data is a B+ tree, a balanced tree where the data pages are the leaves of the tree). If you are expiring old data from such a log table, you are deleting from the left hand side of the tree, and since it is a balanced tree, that triggers a lot of rebalancing – hence it is very slow.

If you rename the old table and INSERT … SELECT the data you want to keep back into the original table, that can be faster. But if the data you want to keep is larger than memory, the indexing of the data will still be slow.

A nice way to handle log tables are partitions. Here is an example. It’s not very cleaned up, but it works on my system.

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New Technology vs Planned Obsolescence

based on an old Google plus article from 2015:

What you observe as Planned Obsolescence is often the natural outcome of fast product cycles that are necessary for any new technology.

When a new thing arrives in the market, it is often barely viable, a minimum viable product. We are remembering the iPhone 1 as revolutionary, but we chose to forget about is slowness, its clunkyness and the very limited feature set it had. And those of us having purchased a car with built-in satnav now have to deal with a car radio where you have to choose between listening to a CD or putting in the outdated CD-ROM with navigation data – and then wait for a minute until you get the route.

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