Common Emitter

2015-06-14

Single vs dual rank memory

In general dual (or even quad) rank memories offer higher performance in server application:
http://globalsp.ts.fujitsu.com/dmsp/Publications/public/wp-sandy-bridge-ep-memory-performance-ww-en.pdf
http://hpc.fs.uni-lj.si/sites/default/files/Memory%20Intel%20Xeon5500.pdf
It's much harder to find any information of memory performance in desktop system. Internet boards present various opinion on single vs dual rank subject, but not supported by any test results. Only info I've found comes from computerbase.de:
http://www.computerbase.de/2014-01/amd-kaveri-arbeitsspeicher/2/
In short: rank number did not make any difference in CPU performance on both Haswell and Kaveri platforms while was significant in GPU tests, especially for AMD where pair of dual rank memories offered 7% better performance than pair of single rank memories on A10-7850K system.

2015-04-05

WIWA HD95 - problemy z pamięcią FLASH

Dekodery WIWA (na pewno HD95 i starsze) cierpią często na problem z pamięcią FLASH objawiający się problemami z uruchomieniem (czarny ekran i/lub resetowanie się po wyświetleniu logo startowego). Czasami problem można usunąć (przynajmniej na jakiś czas - w moim przypadku wrócił po kilku miesiącach) poprzez ponowne wgranie firmware.
W przypadku tego egzemplarza ponowna próba ratowania przez wgrywanie oprogramowania kończyła się niepowodzeniem (błąd upgrade przy ok. 44%).

Serial FLASH: W25Q32FVSIG:

MXL5007T - tuner

Jakkolwiek podejrzanie porada z wątku http://www.elektroda.pl/rtvforum/viewtopic.php?p=12906996#12906996 by nie wyglądała - pomogła w przypadku tego dekodera - po podgrzaniu pamięci FLASH W25Q32FVSIG dekoder uruchomił się a ponowne wgranie firmware powiodło się. Skuteczność metody w dłuższym okresie czasu nie jest mi na razie znana.
Update 2018.12. Problem z pamięcią FLASH powracał, ale kilkukrotnie powtarzana powyższa procedura przedłużyła żywot dekodera o kilka lat. Aktualnie dekoder czeka na wymianę pamięci - tani chip zamówiony został z Chin.

2015-03-14

Google Search spam rant

Whatever Google is doing to fight web search spam does not seem too effective.
Here are search results for "ex-03 usb phone" query:

Custom uninstallers for very niche application (and I'm not even searching for application)? Shit me not. Four out of ten top search result here are domains with algorithmically generated content distributing highly suspicious "uninstallers".
It gets worse: in my personalized (that is when I'm logged in) search results another two similar domains appear in first page thus giving more spam than real content. For comparison: none of these domains appear in top bing, yahoo or yandex search results.
Google search has spam reporting (https://www.google.com/webmasters/tools/spamreportform?hl=en) although my reports here are either ignored or sitting in queue for quite a long time (almost two weeks at the moment).

2014-11-09

Lenovo R500

Fingerprint reader (back of the palmrest)

Quite solid metal chassis

BCM5787 (LAN controller), MAX6622 (temperature monitor), Turbo Memory slot

Intel 5100 WiFi

Matsushita (Matshita) / Panasonic optical drive

Back of the palmrest - IBM/Lenovo/Foxconn

Touchpad

Pros:

solid construction; slightly weaker points are display twisting resistance and palmrest plastic (although metal chassis is directly under palmrest, so this is only minor crackling when pushing at right side)
mat finish and probably very high wear resistance (plain black plastics with no coating of any kind)
still perfectly fine performance for most home/office uses; inexpensive to upgrade with DDR3
low temperature (exhaust at both back and left side) and fan noise (although fan seems to be active all the time)
relatively small touchpad (I've disabled it completely in BIOS as it often generated random clicks for me when typing)
display proportions: 16:10
decent WiFi range / antenna set
great trackpoint (comparing with my previous Dell D600)

Cons:

poor USB port placement - all three are placed on left side near the front and also susceptible to mechanical damage - there are numerous reports of broken ports and they are quite expensive to replace
some noises from switching on-board voltage converters (quite disturbing at first, although I stopped noticing it after some time); surprisingly I haven't hear them when working on second R500 with T5870 processor - it might be individual issue
bad speaker sound quality at higher volume (resonating at some frequencies, especially right one - fixed partially by putting foam layer between speaker and optical drive)
quite fragile when it comes to fluids - that's how my first R500 died; it was just a small amount of water spilled at left bottom keyboard area, but there is nothing to prevent fluids from entering through the crack between palmrest and top bevel and DC/DC converters are very close to this area

Update. While R500 is definitely not resistant to water it turns out mine has survived. At first, after days of drying, laptop was reacting to power switch but screen was blank with inactive backlight. It started working again after resetting CMOS by removing backup cell (well, pity I got this idea very, late buying T500 in meantime).