f*z 发帖数: 421 | 1 "C was developed in the 1970s at Bell Labs. It was originally designed for
and used on the DEC PDP-11—whose operating system, C compiler, and UNIX
application programs were all written in C."
要是C compiler都是用C写的,那些compiler的原码使用什么编译的?上文的C
copmiler是通常我们说的compiler, 还是其他什么东西? |
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d****i 发帖数: 4809 | 2 说Ken Thompson是唯一的UNIX之父显然不符历史事实,应该是他和Dennis Ritchie为共
同发明人,参见UNIX的官方历史:
http://www.unix.org/what_is_unix/history_timeline.html
1969 The Beginning The history of UNIX starts back in 1969, when Ken
Thompson, Dennis Ritchie and others started working on the "little-used PDP
-7 in a corner" at Bell Labs and what was to become UNIX. |
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m******t 发帖数: 635 | 3 你这个简史太简略了,有更详细的。基本上Ken Thompson折腾出kernel和B语言后,
Dennis Ritchie才加入的,Ken单独干下去的话也没有问题。
Ken
PDP |
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d***a 发帖数: 13752 | 4 呵呵...当年第一版用C语言重写的Unix,是在PDP-7机器上开发的。
那机器只有8K个字的内存。为了能让编译器顺利编译,C语言必须精
练才行。为了有高性能,也必须能直接和硬件打交道。 |
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w***g 发帖数: 5958 | 5 45年前发明的语言,当时的机器pdp-7内存是差不多10K,每秒作25万次加法。
现在随便一个台式机,内存都是它的100万倍,随便一个200块钱的显卡,
计算能力可能是它的1000万倍。然后一群人在讨论C语言的指针太难用。
更可怕的是真要做点mission critical的东西竟然还是离不了C语言。
做软件真难啊。 |
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m**i 发帖数: 724 | 6 En?
Is there a similar thing for more modern systems? Or is it easy to get a
PDP-11 emulator? |
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a****l 发帖数: 8211 | 7 俗话说,万宝全书缺只角,大牛也有不知道的东西.
http://www.ni.com/anniversary/chapter1.htm
In 1976, founders Jeff Kodosky, Bill Nowlin, and James Truchard began a
trusting partnership whose nature now characterizes the NI cohesive NI
corporate culture. All employees of the Applied Research Laboratories (ARL)
at The University of Texas at Austin, this trio initially dedicated itself
to building a GPIB interface for the PDP-11 microcomputer.
NI就是做GPIB接口起家的,当然可以算老本了.NI开始做GPIB的时候LabVIEW还没有一点
想法呢. |
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j******c 发帖数: 712 | 8 我的simulation做出来,如果PDP mismatch的话,性能影响挺大的。不知道是哪里错了 |
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j******c 发帖数: 712 | 9 是的,我就是按照您说的方法mismatch的,然后用DFT matri放在PDP两边,得到频域的
相关矩阵。
Ye Li的文章说这样的mismatch是不会改变MSE的,但是我的simulation显示MSE改变很
多,而且很小的SNR就会出现error floor |
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s**c 发帖数: 1247 | 10 A,B n*n,symmetric, AB=BA,A的eigenvalue的multiplicity都是1
求证:A,B能simultaneously diagonalized
i.e. 存在orthogonal的矩阵P,A=PDP',B=PEP',D,E是diagonal的矩阵
3x |
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c*******h 发帖数: 1096 | 11 A对称,所以存在正交阵P将A对角化,也就是A=PDP',D是对角阵。
假设B=PFP'。由AB=BA得DF=FD。
矩阵DF的第ij个元素是d_ii*f_ij,矩阵FD的第ij个元素是d_jj*f_ij。
所以f_ij=0如果i不等于j,即F是对角阵。
其实这个命题是充要的,而且A、B不必对称(当然要将P转置变成P逆)。
前两天刚好有个朋友跟我提了这个定理,
我说这下好了,很多人问什么情况下AB=BA,充要条件就在这。 |
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m***i 发帖数: 898 | 12 DrNewbie,
在版上看到你热情而详细地回复大家的帖子,知道你是个热心肠的人。我目前也碰到了
dental insurance 的问题,希望得到你和其他朋友的帮助。
我从去年7月份加入metlife的牙医保险, 一直没有用过。上个月发现一颗牙有个小洞
,于是就近找了个PDP network内的白人牙医开始看牙。一开始做了口腔检查,拍了全
口x-ray。告知我需要补6颗牙,同时进行洗牙。我当时没有异议,因为自己一直以来牙
齿都不太好。按照她的计划分次完成了洗牙和补牙。现在陆续收到了insurance EOB,
发现了如下问题:
1. 洗牙时,hygienist 告诉我将会在两周内分两次进行,保险都会cover。 给我的帐
单显示:
05/16/10 Adult Prophylaxis $77
Comprehensive Oral Exam $74
06/03/10 Adult Prophylaxis $77
Periodic Oral Evaluation and Oral Cancer Screenin |
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j******8 发帖数: 12 | 13 地点:上海;要求:CNS相关专业,临床医生背景;项目类别:AP(新药3期)
Basic Function:
Provides medical input to all areas of clinical development projects
related to CNS in AP including the Product Development Plan (PDP), Study
Protocols, case report forms (CRF), data evaluation, clinical study report,
publications, NDA submission and response to regulatory enquiries. Ensures
that all documents are developed with sound, valid clinical judgment in a
timely manner Represents PDCC-M in the Local or International Project Team (
I... 阅读全帖 |
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j******8 发帖数: 12 | 15 地点:上海;要求:CNS相关专业,临床医生背景;项目类别:AP(新药3期)
Basic Function:
Provides medical input to all areas of clinical development projects
related to CNS in AP including the Product Development Plan (PDP), Study
Protocols, case report forms (CRF), data evaluation, clinical study report,
publications, NDA submission and response to regulatory enquiries. Ensures
that all documents are developed with sound, valid clinical judgment in a
timely manner Represents PDCC-M in the Local or International Project Team (
I... 阅读全帖 |
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j******8 发帖数: 12 | 16 地点:上海;要求:CNS相关专业,临床医生背景;项目类别:AP(新药3期)
Basic Function:
Provides medical input to all areas of clinical development projects
related to CNS in AP including the Product Development Plan (PDP), Study
Protocols, case report forms (CRF), data evaluation, clinical study report,
publications, NDA submission and response to regulatory enquiries. Ensures
that all documents are developed with sound, valid clinical judgment in a
timely manner Represents PDCC-M in the Local or International Project Team (
I... 阅读全帖 |
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f**********r 发帖数: 2137 | 17 非square matrix也可以有特征值么?
N=M就好办啊,A=PDP^(-1), P是特征向量组成的矩阵,D是特征值的对角阵 |
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f******r 发帖数: 11 | 18 想立一个命题帮助证明一个其它东西。但是总觉得这个命题有点问题。请大家看一下好
吗?
命题:任何一个满枝方矩阵都可以表示为一个正交矩阵乘以一个对角矩阵。
我的想法是:
A is a square full rank matrix.
then AA' is symmetric square. AA' = PDP' (eigen decomposition).
so A can be PD^(.5) |
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l******n 发帖数: 38 | 19 AA' = PDP' 的 A解不唯一,不一定是PD^(.5)。
A=UDV' with U,V orthonormal and D diagonal. |
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s*******e 发帖数: 1385 | 20 为什么不能用spline?关于model的解释不能一味的看model formula,可以看predict
vs actual或者PDP之类的。 |
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p*******g 发帖数: 809 | 22 超级赞。不过众牛人汇聚UCSD把PDP搞得热火朝天波澜壮阔的历史讲的有点少了:)
Terry现在是科学院院士、工程院院士 以及 医学院院士。 |
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z**********e 发帖数: 22064 | 23 http://hx.cnd.org/?p=118388
王克斌
1979年秋,研究生院的课程修得差不多了。这时麻省理工学院的丁肇中教授领导的小组
和高能所联合在玉泉路办了个训练班, 简称丁训班。学生在班上学习一些高能物理实
验的基本知识和方法。学成后,部分人会被选送到德国的汉堡。那里有个高能物理实验
室,得赛(Desy),其中有台马克J探测器属于丁先生的小组。这个小组从实验数据中
发现了三喷注事例,被解释为两个夸克和一个胶子。
赵忠尧导师介绍我参加这个训练班,不管将来能否会去德国,但总会学到一些有用的知
识。参加这个班的还有几位105班的同学,郑林生先生的研究生赵天池,叶铭汉先生的
研究生漆纳丁和马宇培。纳丁在张鸿欣班长去美国后,继任105班的班长。我们几个应
当算旁听的,正规学员有科技大学的冯正勇等,考进丁班的研究生吴守庠、汪尧勋等,
还有还几位年长的老师来自南京大学和上海原子能所。
按照老师的决定,我骑着自行车驮着铺盖卷离开林学院,来到高能所,住进新盖不久的
宿舍楼的一层。丁训班的活动安排在一座新楼里,属于唐孝威先生领导的应用室,他们
与丁肇中小组有密切的合作关系。这个组的大部分科... 阅读全帖 |
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w*******y 发帖数: 60932 | 24 Link:
http://www.macmall.com/p/Fantom-Drives-External-Hard-Drives/product~dpno~7532251~pdp.ejchfbh
List Price : $114.95
Your Price: $99.99
Mail-in Rebate(s): $50.00 (50.01%)
You Save: $65 (57%)
Your Final Price: $49.99
NOTE: this contains two macmall rebates. I've heard a lot of crying about
how risky they are so YMMV.
> Save $25 via mfr. mail-in rebate with the purchase of a Fantom Drives
GD1000EU. Offer ends 6/30/10; must be postmarked within 30 days of purchase.
Limit ONE rebate per offer |
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w*******y 发帖数: 60932 | 28 1920x1200, S-IPS, Displayport, and less than $300 after rebate. What more
can you ask for? (120Hz?, LED backlighting?, 30"?) Well...no this doesn't
have that, but its still a good deal.
Anyhow, go to Macmall:
http://www.macmall.com/p/HP-Monitors/product~dpno~8086055~pdp.gbbaghb
for the deal!
This is the lowest price I've ever seen on this monitor since being released.
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w*******y 发帖数: 60932 | 29 The Panasonic TC-P58S2 58" Class VIERA S2 Series Plasma HDTV is great for
sports and cinema-quality movies. Our Neo PDP technology delivers sharp,
detailed image and remarkable brightness; all with lower power consumption.
LINK:
http://www.6ave.com/shop/product.aspx?ref=Froogle&sku=PANTCP58S2
coupon code "AFL4COUPON" gives you 4%off.
Price: $1207.13 - 4% = $1158.84 + Free Shipping
Features included:
* Screen Size 58" Class (58.0" diagonal)
* Contrast Ratio Native: 2,000,000:1
* Aspe... 阅读全帖 |
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w*******y 发帖数: 60932 | 30 Enjoy Full HD 1080p Sonypicture quality and an innovative six-degree tilt
for improved viewing at a lower level with the sleek and slim Edge LED
backlit Sony BRAVIANX700 LCD HDTV. Also features built-in Wi-Fi
connectivity for convenient access to your favorite entertainment apps
including movies, TV shows, videos, music and more.
Link:
http://www.macmall.com/p/Sony-Consumer-Electronics/product~dpno~8048870~pdp.gahfiah
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w*******y 发帖数: 60932 | 31 This is similar deal to last week samsung deal, but it is LG this time! Hope
Amazon can price match it!!
Link:
http://www.frys.com/product/6181499
General:
Depth: 12.2 in
Digital Television Certification: HDTV
Dimensions: With stand
Enclosure Color: Gloss black
HDCP Compatible: Yes
HDMI Ports Qty: 3 port(s)
Height: 30.8 in
PC Interface: VGA (HD-15)
Product Type: 50 plasma TV
Timer Functions: Sleep
USB Port: Yes , 1 port(s)
Video Interface: Component, composite... 阅读全帖 |
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w*******y 发帖数: 60932 | 32 Oringinally this was going to be an online Thanksgiving sale only but it's
up now!
Link:
http://www.sears.com/shc/s/p_10153_12605_05775620000P?adCell=HPpanasonic&adCell=W2
Product Description
Panasonic TC P58S2 - 58" VIERA S2 Series plasma TV - widescreen - 1080p (
FullHD) - 600 Hz - HDTV
VIERA S2 Series Plasma HDTVs are great for sports and cinema-quality movies.
The Neo PDP technology delivers sharp, detailed image and remarkable
brightness - all with lower power consumption.
* 1080 TV lin... 阅读全帖 |
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w*******y 发帖数: 60932 | 33 These are compatbile with Wii Motion Plus with or Without the Jackets .I've
been looking for these to come down in price and these are the cheapest I
have seen them.
Product Features:
An Officially licensed Energizer product, so you know its quality.
Compatible with Nintendo?s Silicone Jacket and Wii Motion Plus.
Comes with 4 (or 2 depending) rechargeable battery packs!
Saves you money that you were previously spending on conventional batteries.
Easy to read lit indicator lets you know when it's... 阅读全帖 |
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w*******y 发帖数: 60932 | 35 Been watching TVs and this looks pretty good. The deal was around for Black
Friday but it's back again. (See previous deal here)
Product Description
Panasonic TC P58S2 - 58" VIERA S2 Series plasma TV - widescreen - 1080p (
FullHD) - 600 Hz - HDTV:
http://www.sears.com/shc/s/p_10153_12605_05775620000P?prdNo=2&blockNo=2&blockType=L2
Sears Item# 05775620000 | Model# TC-P58S2
Reg. Price $1499
Sale Price $1099
VIERA S2 Series Plasma HDTVs are great for sports and cinema-quality movies.
The Neo PDP ... 阅读全帖 |
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w*******y 发帖数: 60932 | 37 Use code: EXTRA10WISHES at checkout and the price drops from $1099.99 to
989.99.
Today only! Electronics on Sale. Use Coupon Code EXTRA10WISHES at check out
to receive discount. Offer ends 18-Dec-2010 See details.
No interest for 24 months if you use your sears card.
Link:
http://www.sears.com/shc/s/p_10153_12605_05775620000P?keyword=tc-p58s2&sLevel=0&prop17=TC-P58S2
Product Description
Panasonic TC P58S2 - 58" VIERA S2 Series plasma TV - widescreen - 1080p (
FullHD) - 600 Hz - HDTV
VIERA S2 S... 阅读全帖 |
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w*******y 发帖数: 60932 | 38 Apple 13.3" MacBook Air 1.86GHz, 4GB RAM, 128GB Flash Storage, NVIDIA
GeForce 320M (Z0JG-4GB)
1.86GHz Intel Core 2 Duo, 4GB DDR3 SDRAM, 128GB Flash Storage, NVIDIA
GeForce 320M, 13.3" LED-backlit glossy widescreen display, AirPort Extreme
Wi-Fi 802.11n, Bluetooth 2.1, SD card slot, FaceTime camera, Built-in
battery, Precision aluminum unibody
$1,318 at Macmall:
http://www.macmall.com/p/product~dpno~8233537~pdp.gcgaeie
:
I have been researching these for a while (online and hands on in store) and... 阅读全帖 |
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w*******y 发帖数: 60932 | 39 SAMSUNG PN43D450 for $449
43" PLASMA HDTV,CONNECT-SHARE JPEG,2 HDMI INPUTS
Plasma TV is the true cinema lover's TV; the 43-inch Samsung PN43D450 Plasma
TV delivers all the bold contrast and color of plasma, with the advanced
features and design that Samsung is known for. Samsung's Plasma Plus One
Design sets this TV apart, with an extra inch of screen compared to
similarly sized competitors' models. For TV shows and movies, the innovative
600Hz subfield motion technology renders even the fastes... 阅读全帖 |
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w*******y 发帖数: 60932 | 41 16GB MICRO SDHC CLASS 10, PATRIOT
Link:
http://www.frys.com/product/6490172
$24.99 - $7.00 Rebate = $17.99
$7.00 Mail in Rebate valid from 2011-07-08 to 2011-07-14
Mfr: PDP Model: PSF16GMCSDHC10
FRYS.com #6490172 UPC: 815530010876
The Patriot LX Class 10 MicroSDHC flash memory cards offer blazing
performance for mobile devices. The LX Class 10 MicroSDHC memory cards meet
the latest SD Association specifications and provide a minimum sustained
write speed of 10MB/s. Fast enough to rec... 阅读全帖 |
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w*******y 发帖数: 60932 | 42 DDR3 4GB 1333MHz DUAL G2
Mfr: PDP SYSTEM INC
Model: PGD34G1333ELK
FRYS.com #6504573
UPC: 815530010975
Link:
http://www.frys.com/product/6504573
Online Current Price: $29.99
Shipping (Basic): $1.99
Rebate ($25.00)
Final / Net Price: 6.98
Rebate is attached.
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w*******y 发帖数: 60932 | 47 Nike Benassi Swoosh Men's Slide Sandals
Link:
http://store.nike.com/us/en_us/?l=shop,pdp,ctr-inline/cid-10070
Add both of these promo codes in your cart at checkout:
Promo Code- ADVANTAGE - 25% off Clearance
Promo Code- SWOOSH - Free Ground Shipping
Ends 11/30/11
I know that these Promo codes have been posted, but I want everyone to see
with these 2 promo codes added in, on how good of a deal you will be getting
for these sandals.
They are usually $19.97 shipped, but with the 2 promo codes add... 阅读全帖 |
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