m********l
发帖数: 791 | 1 【 以下文字转载自 JobHunting 讨论区 】
发信人: mechanical (mechanical), 信区: JobHunting
标 题: 有必要旁听 operating system design吗？
发信站: BBS 未名空间站 (Wed Aug 22 15:05:36 2012, 美东)
转专业到CS，学过C++，完全没有实际项目背景。会Java和web scripting。以后想做码
工。
课程大致描述：
language: C/C++
environment: UNIX
topics:
1. mutual exclusion/synchronization
2. memory management
3. scheduling
4. I/O management
5. thread
教授说会用到两个library: posix & semaphore
有必要旁听么？跟做projects么？我这学期想要ＭＳ毕业，还有part-time RA, 有点忙。
谢谢！ |
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g********r
发帖数: 187 | 2 Oracle8.X doesn't allow dash '-' in its SQL request. I need to do some minus
operation in SQL, how to write the SQL?
Thank you. |
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s******r
发帖数: 1524 | 3 update table2 set table2.maxday = (select max(day) from table1);
Table2 have only one record. table1 have more than 10,000 records. Want to get
max(date) and update table2.
run it and got error message:
"Operation Must Be Updatable Query". I know it is the link problem. No idea ho
w to deal with it or is there any other way to work on it? Thanks. Help please
. |
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a*******t
发帖数: 891 | 4 what database are you using?
the query itself can't run in MS Access.
have you tried it in the database itself?
Table2 have only one record. table1 have more than 10,000 records. Want to get
max(date) and update table2.
run it and got error message:
"Operation Must Be Updatable Query". I know it is the link problem. No idea ho
w to deal with it or is there any other way to work on it? Thanks. Help please
. |
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h********i
发帖数: 32 | 5 个人觉得data structure,operating system在dba中没用
主要学sql, unix, shell scripting就能搞好dba了
在美国的职场混，关键是能用英语和大家打成一片，埋头写程序都没有出头之日；少一点geeky,多一些street smart |
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f******l
发帖数: 26 | 6 the operator "-" in
z= -x
and
z= x-y
are two different things, how to define them to make a difference? |
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g**d
发帖数: 77 | 7 A very interesting comments from Nanog. 1-2 mth ago, I came across a similar
article. Verizon engineers tested on FiOS network that the max download
speed is 6-8 Mbps even the retail bandwidth is 100Mbps becoz most of
webservers are using old TCP stack.
So we have 2 bottlenecks here, 1 is on the PC OS, another 1 is on the server
side.
From o*********[email protected]; on behalf of; Leo Bicknell [b******[email protected]]
Subject: The next broadband killer: advanced operating systems?
Windows Vista, and next w |
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u*****e
发帖数: 47 | 8 我们公司需要招人，operation engineer
主要职责范围：
1: network
2: linux system
3: AWS
4: script
5: system monitor
不一定要全部都强，但是能cover的越多越好。
希望candidate有责任心，有经验。
我们公司在加州湾区。我们公司是视频通信的startup。有兴趣的朋友，请发私信。 |
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c*****t
发帖数: 1879 | 9 Show me your code first :)
FYI, ^, |, &, ||, && each has a different operator precedence. I
would STRONGLY suggest you to put parenthesis around expressions
involve them. |
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X****r
发帖数: 3557 | 10 I didn't read the whole thread so I must have missed something here,
but isn't operator precedence issue should have solved in compilation
to byte-code? |
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R*******r
发帖数: 104 | 11 Valuable? I think not. There are too many confusions in operator overloading,
at the end of day, a.add(b) is ugly but tolerable, but inproper usage of a+b
can cost you entire day.
of |
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c********l
发帖数: 77 | 12 需要复习一下Operating System的基础知识，请问现在比较流行的教材有哪些啊？多谢
指教！ |
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w*****j
发帖数: 49 | 13 hi, everyone. I just started learning operating system. And I heard ubuntu
is difficult to compile.(is it true?) so if i want to learn os, should i
install a more professional linux and if that's so, what version should i
choose?
Thank you for your patience to go through this post, i'm really a novice in
cs. |
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c**u
发帖数: 2230 | 14 image we have two integers N1, N2.
If we want to get the division, we do : division = (int) N1/N2;
if we want to get the reminder, we do: reminder = N1 % N2;
The interview question is how to get both division and reminder in just one
operation, instead of two? |
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k****f
发帖数: 3794 | 15 你得定义什么叫做一个operation
是一个汇编指令？一个函数？一个C语句？
one |
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S*****H
发帖数: 90 | 16 What is the correct value to return to the operating system upon the
successful completion of a program?
A. -1
B. 1
C. 0
D. Programs do not return a value. |
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n*****e
发帖数: 17 | 17 我知道operator overloading 是不能参数一样的
可是这里有一个是constructor,所以不知道会不会有特别
我写了一个test program,好像没有问题，可是程序复杂了，好像有问题，很奇怪
如果要实现这样的两维数组想表示成p(i,j)或者别的某种形式，怎么做比较好？请大侠
帮忙！
test program 如下：
#include
#include "Point.h"
using namespace std;
int main() {
Point pt(2,2);
pt(1,1)=1.;
cout<<"pt[1][1]= "<
cout<<"pt[0][0]= "<
return 0;
}
先是结果为：
pt[1][1]=1
pt[0][0]=0 |
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k****y
发帖数: 781 | 18 要实现子类的assignment operator 怎么访问父类部分的的private member从而实现
copy |
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c*****t
发帖数: 1879 | 19 You can't. The parent classes should have their own assignment
operator and you just need to call them, and take care of the new
members introduced by this class. |
|
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k****y
发帖数: 781 | 21 Are you sure about this?
I think calling Base::operator=(r) is right |
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N********n
发帖数: 8363 | 22 Adding assignment operator to sub-class is messy if the base class
doesn't have one already. I suggest you drop it unless you really
wanna re-code the base class. |
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k*k
发帖数: 508 | 23 that's not the point.
problem we discussed here is how to manipulate the private
member in an indirect way, i.e., with *existing* method or
override operator in the base class. Your way to do it is
one possible solution. You called it easy, yes, it's easy.
But if the base class doesn't provide such an "easy" way,
we need to use those "tricky" method. I am not blaming you
for anything. I just want to point the fact that what you
want may not always be there for you. |
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k*k
发帖数: 508 | 24 sigh. I am not saying "access", but "manipulate indirectly"
you are still doing it in OO way but an indirect way. you don't
access the private member in base class directly, you access them
through what base class provided (e.g., the operator =()). of coz
i agree with your points of thinking in OO. But honestly speaking,
OO itself is not that perfect. |
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z*********8
发帖数: 2070 | 25 for a large integer i which has L bits, will the shift operation cost
constant time or O(L)? |
|
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q*****g
发帖数: 72 | 27 means use global operator new |
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i**p
发帖数: 902 | 28 Is "Class C, the class of the object that ap points to" the same as "The
class of the object passed to the dynamic_cast operator"? |
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i**p
发帖数: 902 | 29 Make it more clear of my understanding.
A *ap = new C;
B *bp = dynamic_cast(ap);
"The class of the object passed to the dynamic_cast operator" is A, not C,
even though ap points to object of C. |
|
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c********x
发帖数: 84 | 31
it depends which version of C++ standard you are talking about, for the new
version, operator new or new[] can throw a bad_alloc exception if no enough
memory. The old version new just return 0. |
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j****e
发帖数: 140 | 32 I want to get 2^x. x <32. which would be faster, to lookup a table or to use
bitwise shift operator < |
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w****g
发帖数: 4 | 33 从编译器产生的代码看，有dtor时, 检查是否为0，是0则马上返回。
没有dtor时，直接调operator delete()
不知道这样设计有什么依据 |
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g*****u
发帖数: 298 | 34 85. You have an abstract computer, so just forget everything you know about
computers, this one only does what I'm about to tell you it does. You can
use as many variables as you need, there are no negative numbers, all
numbers are integers. You do not know the size of the integers, they could
be infinitely large, so you can't count on truncating at any point. There
are NO comparisons allowed, no if statements or anything like that. There
are only four operations you can do on a variable.
1) You |
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g*********s
发帖数: 1782 | 35 bit operation? It looks like theoritical computing ah.
about |
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t****t
发帖数: 6806 | 36 你问得很好啊, 是那个A的对象调用了operator new呢? |
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s***e
发帖数: 122 | 37 不是很熟悉这种比较深的东西，不过我的理解是，非static的成员函数都事实上隐含了
第一个参数this，所以它的参数应该就跟应该重载的operator new不match了吧。 |
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c**a
发帖数: 316 | 38 。。。
编译器不是说了嘛
编译器这么说就是暗示， operator new 必须是 static的， 您老忘记加了，我给免费
加上了
你想过thrust说的了吗？ |
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p***o
发帖数: 1252 | 39 Oh, yes. But implementing operator T* for [] is strange enough.
given. |
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r*********r
发帖数: 3195 | 40 shouldn't g++ pick "operator []"? the other path requires more "effort". |
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i***h
发帖数: 12655 | 41 [] by default is pointer reference
I think this way is more elegant than overloading [].
[] overloading can be used for more complicated index operation. |
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d**********o
发帖数: 41 | 42 我想把一个class A的new 重载成：
void* operator new(size_t sz, string s){...}
在这个class A里有一个静态的vector，记录string s
也就是说这个vector在每次动态分配空间的时候记录一些信息，比如__FILE__, __LINE
__
但是编译出错说C1001 an internal error has occurred in the compiler, 看了半天不
知道怎么错了
OS: windows XP
DE: VC2008
code 见下 |
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d**********o
发帖数: 41 | 43 #include
#include
#include
#include
#include
using namespace std;
class A{
static vector log; //log for dynamic mem alloc, static
string name;
public:
A(string s):name(s){}
void* operator new(size_t sz, string s){
log.push_back(s);
void* p=0;
if(!(p=malloc(sz))) throw bad_alloc();
return p;
}
void showLog(unsigned int index){
cout<
}
};
vector |
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d**********o
发帖数: 41 | 44 如果我把静态的vector成员变成vector，就都正确了
是不是编译开始的时候分配静态成员内存的时候vector的大小不能确定？
下面的程序是正常的
//=============================================
#include
#include
#include
#include
#include
using namespace std;
class A{
static vector log; //log for dynamic mem alloc, static
string name;
public:
A(string s):name(s){}
void* operator new(size_t sz, int s){
log.push_back(s);
void* p=0;
if(!(p=malloc(sz)) |
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t****t
发帖数: 6806 | 45 try not to use "string s" in prototype
use const string& s
i.e.
void* operator new(size_t sz, const string& s)
but anyway, internal errors are always compiler bug
LINE
天不 |
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j******i
发帖数: 21 | 46 I am using the the backtick operator to call a SAS program to generate some
results. My problem is it can only use the user name: nobody. So I have to
set up all permission with 777 for all data and log files. It create a lot
of security concern. Anybody know how to fix this issue, say, perl call SAS
program under a specific username with password. Thanks a lot! -- johnjshi@
gmail.com |
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b***y
发帖数: 2799 | 47 请问func(para1, para2)中的comma是comma operator吗? para1, 和para2的
evaluation的顺序是不是确定的? |
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c******t
发帖数: 1500 | 48 Silberschatz - Operating System Concepts - English 7Ed 2006 |
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