2014年10月1日 星期三

感同身受

在回來的高鐵上,翻出行前塞進平板的家政婦三田來看。原本只是為了打發時間,打算把之前看得斷斷續續的劇情,一次看個完整。

但是第一集看到一半,就流淚了。沒有辦法把一集看完。 因為,還有好多事沒有和你作,還有好多話,沒有跟你說。就如同劇情,你走得太突然。還沒有辦法接受這樣的事實,即使已擺在眼前。而已經七七了嗎? 就這樣和你永別了嗎?

虚構的劇情不管多麼荒謬,多少不合常理,能夠成功,始終是因為和讀者、觀眾的經驗契合,能夠打動人心產生共鳴。

2014年8月7日 星期四

Google Play 變成日文版本

所以這算是移民到不同國家版本的密技嗎?

作的是


  1. PC VPN 到日本網路,因為 Google Play 會認 IP 判斷國家。不可以用手機,因為似乎是手機 SIM 卡國別優先於 IP  國別
  2. 在 Google Play Books「買」了一本0元促銷的漫畫書。但因為先前有 Nexus 7 送的日幣額度,是用日幣結帳(0圓)。不確定沒有餘額也沒有日幣信用卡的話行不行。
  3. 接下來這個帳號下所有 Android  裝置通通重新要求確認了一遍 EULA, 就像被清除設定重來一遍一樣。

然後手機、平板上的 Google Play 看到的內容都變成日文版本。如排行榜等。商店也可以看到日本版有開放的 Play Video, Books, 但沒有日本還未開放的 Play Music。

2014年3月26日 星期三

What is possibly NVLink?

nVidia today announced NVLink claiming 5x-12x bandwidth of PCIe. And should be used together with IBM POWER systems.

What's possibly NVLink? what's it made of?

Previous tech on bus link increased bandwidth by growing bus width. 4-bit, 8-bit, 16-bit, 32-bit. e.g. like PCI bus or parallel bus. The problem of growing parallel bus width is that things got complicated when ilnk is wider and longer. It is harder and harder to keep all signals in sync. So the on-board PCI bus stopped at 64-bit. Parallel SCSI for inter-enclosure stopped at 16-bit. They both changed the direction toward high-speed serial links. So now we have PCIe and SAS.

But the high-speed serial link has its shortcomings too. Serial links though eliminated the need to sync across all signals, has high demand for serdes design, high-freq signal handling, etc. It is advancing, but not as easy as adding more signal links. The latest PCIe gen3 grew from 5GHz to 8GHz, less than doubled clock rate. The other bahdwidth improvement came from more efficient 128b/130b LDPC.

As the most bandwidth demanding component, GPU has lead the way of link and memory bandwidth. so we have various GDDR, ultra-side memory bus, and the primary user of PCIe has always been GPU before the AGP, graphics-centric bus, was done.

So what can NVLink be?

According to the slide nVidia provides, GPU and CPU still have PCIe link between them. So it is possible NVLink is used as a wider side channel for more efficient data movement. Much like what SLI and Crossfire did in the past. Only this time CPU joins the party. This makes it look more like the internal connect found in recent AMD APUs, but for inter-chip.

But where does the 5x-12x bandwidth come from?

It is possible that nVidia and IBM came out tech similar to QPI or HT for chip-level communications. Given that serial link clock is unlikely to get huge boost, It is more possible that NVLink gets the 5x ratio partly from higher clock/transaction. Say 1.5x for chip/board-optimized usage. The other mostly come wider link. PCIe is currently limited to x16 configuration. For specific usage optimization it is possible nVidia choose to widen the link, provided the link distance won't go too far. x32 link is a safe bet, and x64 is a bit ambitious.

Another inter-chip connect example is the newly disclosed OPIO from Intel, used on Haswell parts. 16-bit x 4 clusters/direction x 6.4GT/s gives 51.2GB/s per direction or "102.4GB/s bidirectional".OPIO is focused on on-package low-power interconnect. NVLink is unlikely to achieve the same level of power consumption.

The bad thing is nVidia is always light on technical details. Sometimes even distort or hide truths. The good is that IBM is more open in this regard. We will see.

2014年1月6日 星期一

Red 2

就是個續集...

原來爽快的槍戰還在,請了更多大牌來共襄盛舉。

但是劇情鬼扯蛋,只是為了打鬥而亂掰一通,銜接毫無邏輯可言。Helen Miller 的皺紋拍得有夠明顯想忽視都不行,第一集中的優雅完全被模糊焦點。李炳憲一開始還有狠勁,被說得後變成個搞笑角色。

難怪 IMDB 只有 6.7。是個不需要帶大腦看的片來著。