算法交易-Bali

As to the complexity level of problems, developers in Microsoft, who deal with coding, are probably taking one of the most challenging jobs in the world. But another engineering role, program manager, is not easier in any sense. Before I explain why, let me illustrate what typical product teams look like.

In the diagram, group manager often runs a team owning individual components or feature areas, say, one spell checker DLL in office; a product unit manager owns a product, say Outlook; while a general manager runs a product family, say Office. One compelling advantage Microsoft possesses is that its products are designed to work together seamlessly. For example, in a recent CIO.com article, 10 Reasons to Use Microsoft Outlook for Your Company’s E-Mail, 8 of 10 points is actually about interoperability with other software.

Managers define strategy, Developers write code, testers test code, what do PMs do? Well, it is really hard to define – there is even no consensus within Microsoft. However, one thing is clear – PMs do anything except coding(unless they have to to drive projects meeting strategic goals. Enable right things get done right. Figure out gaps and fill them. The role is something like concrete among brick walls. (cartoons on the right)

If you take a look at PM’s position, blocks with black bold border, in the organization hierarchy, you will get the challenges here. PMs are supposed to lead their peers to work towards the right direction.

“You are not my boss. Why do I have to listen to you?”

This question gets down the topic of “Lead without Authority”. Before you read along, I have to clarify that I am not a PM expert, but I (0) I’ve been a PM for quite a while, (1) work with great PMs, (2) learn and try most fundamental things which work well, (3) I faced similar situations for many many times, either in schools, or various organizations. Here is my sharing.

• Charisma. You might be incredibly raw smart – you can optimize an algorithm from O(N*N*N) down to O(logN), or you might be able to design a system of .9999 availability, extremely secure, and super cheap compared with competitors… That doesn’t mean you can be a good leader. Instead, many of the best leaders, however, will point to the fact that they were “C” students(From Source).
• Credibility. It is the key to make people follow you. It works like stock value – hard to build, easy to lose. Be careful of it always. Do right things right. Bring something valuable to the team. Your credibility will accumulate gradually. Do what you say, and say what you mean.
• Consistency. People hated to be randomized. Don’t always change directions. Clear goal.
• Partnership mentality. Low ego.
• Help others great. Most influences are indirect. People often complain about “over-managed, but less supported”. (Check out photo on the right)
• Lead by showing, not lead by talking only. Get your hands a bit dirty. Leaders should be willing to do anything they tell their reports to do. Show domo, mock UI, prototypes to other when presenting a new way to do things.
• Has sense of people. Most basic thing is How to Win Friends and Influence People. Learn to inspire people. Always be positive in every aspect.
• Communicate. Communicate. Communicate. Listen. Ask questions. You can be introverts, but have to be proactive. Be transparent. Understand your audience – strength, weakness, style, and figure out most effective approaches.
• Relationships enhance communication. Invest time in talking to people interactively. When you need to request advice, an opinion, or a task, you can talk to people from a healthy and positive place.
• Sharpen your vision. Look around. Look ahead. This helps in making sound decisions.
• Start to drive teams with strong pseudo leaders
  • Talk to them especially leaders or submarine leaders, get to know what are their likes/dislikes, Ask: How can I help you guys? Win their support.
  • Build credibility. Bring something invaluable to the team, for example, build up strong relationships with a partner team, present a competitor research report, improve team visibility
  • Before making changes, present it to the leaders in private, say 1on1, to reach rough consensus before it goes public.
  • Help others great. Let them get the credit.
• Conflict Management
  • Focus on goals, not conflicts themselves. Not a question of smart or dumb.
  • If you can control your emotion well enough, 25% of conflicts will go away.
  • Overwhelming majority of conflicts is just because of perspectives and different values. Try to figure out stories of other people’s side. People often come to the same solution when presented same set of information. Use negotiation tips. Keep win-win in mind.
  • In worst case – when you have to resolve unavoidable conflicts, say 5 pies for 10 kids, make sure put a fair decision-making system in place, which is often a engineering way.
• You can reward desired performance even without authority
  • Promotions, raises, bonuses are not in your list, but you can affect them in indirect ways
  • Fame. Complimenting an employee on a job well done at a staff meeting or in front of company officers can be extremely rewarding
  • Increased trust. For example, give top performers the freedom to work in a more self-directed manner.

Today I got a mail from lakequincy.com, saying:

“Hi Bill,

I noticed that you were never able to plug the Lake Quincy Media ad tags into your site. Are you still interested in earning revenue from displaying ads targeted to Microsoft developers? If so, you can get your tags from here: <certain link>

Let me know if you have any questions or if you’ve decided against running the ads and I’ll set your account to inactive for you.”

I even forgot that I resgistered in their site. To encourage such great customer service, I go ahead to try how the AD really works for me; finally decide to put a small square in the side bar. You can easily find it now if you scroll down a bit and pay attention to the left side bar. Let us see how many dollars I can make after one or two quarters. By putting an AD to the blog, it looks more of-the-business, doesn’t it? Of course, you can bid for that AD position. :- )

Update(2/26/2009)

The AD is disabled temporarily due to security alert.

This is also one of my half-completed ideas years ago. It was recalled recently by two stories:

Stories

#1: One of my team mates lost his Outlook email archive due to a mistaken operation. He is very upset because all of his emails in past two years are gone, unrecoverablly. Suggested Outlook mail file is 2GB, but people can easily drive it up to 10GB and often notice this too late. As what he said in MSN signature, “my archive, 555…”

#2: While I was browsing one of my favorite bloggers – Brad Abrams’s blog, ran into a shocking post, Help! My hard disk crashed. He can afford a new disk, but he need the data – especially “the pictures of the kids recent birthday party”. In the comments, people suggested various ways to recover it, unfortunately looks like no luck.

This leads to the most basic questions: why people don’t backup data even if they know they are in the risk of losing them? Probably because of:

1) The chance is very tiny

2) Current backup solutions are not “good enough”

For 1), although it might be true, but remember the result might be cataclysmic. Let us take a look at what is going on about 2).

Existing Backup Solutions

Traditional C/S – Most of current backup solutions are based on traditional C/S architecture. Assume one use 40% of 500GB disk drive on average; it is still a big capacity for enterprise with thousands of staff. Backup time is also another concern. Let me illustrate this with some math. For a backup server with two 1-Gbit NICs, its max throughput is about 200MB. If backup window(people are sleeping) is 10 hours, it means it can back up about 7.2TB(2*100*3600*10MB) data. Obviously it is hardly scalable along with business expansion.

Online backup – People can turn to AWS S3, or Azure SQL Data Services to simplify things on their own side. But this doesn’t make things even better if you look at current network speed. Calculating data is much easier than moving data around.

My P2P Backup System

p2p backup comes with several inherent advantages in handy:

1) No additional hardware expense. People often have at least 30% capacity left; we can leverage that for backup space.

2) No obvious network bottleneck.

Some people might also list “no single point of failure”, but that is not true. Let us take a look at how BT works, a general P2P network.

Basically here are what happens in P2P network – peers need talk to a central coordination server(i.e., Tracker in BT system) to get info about other peers, and then talk to individual peers about real data exchange. These two steps are essential. Single Point of Failure(SPOF) can happen in the coordination server. You may argue that you can enhance its reliability by techniques like mirroring, but does it look like over-heavyweight? We have many reliable services running by full time IT guys, why do we bother to re-invent the wheel? Several services can be utilized, such as AD, Sharepoint, exchange, which allow customized data writing. Data needed written into a central place would be:

1) Peer list by <IP, port>

2) Other meta data such as backup network name, Software RAID level

Of course, we need do compression, encryption, incremental backup, scheduled backup in the solution. I may do investigation later and update the post.

Also see other backup solutions

http://www.storegrid.com/index.html – select a folder, then backup, traditional

www.streamload.com – Large net disk, Upload your files to streamload, then view it, or email it to someone else.

http://www.beinsync.com/ – Access you computer: install a mini PHP web server onto it.

http://base.google.com/base/about.html – In about 15 minutes, your item will have a unique web address and be visible to the world.

http://www.openomy.com/ – openomy is an online file storage system designed to be a platform for Web 2.0 applications, built by Ian Sefferman

Memory leaks are always headache of developers. Do .NET developers no longer bother to worry about memory leaks because of garbage collection? Yes and NO. GC periodically find objects that cannot be accessed in the future and then reclaim the resources used by the objects. GC achieves this by maintaining a list of references to live objects. When this mechanism is broken, memory leak happens.

There are many reasons to leak memory. In addition to calling unmanaged code from managed code, another one of general cases is about event handler. If you do this:

Foo.FooEvent += new EventHandler(MemoryLeaksHere.Method);

When you complete using MemoryLeaksHere, but you are still using Foo, then MemoryLeaksHere will still remain alive as well. MemoryLeaksHere object will leak memory as a result of failing to GC.

Let us take a look at one simple example first.

using System; namespace MemoryLeakSample { class Foo { public static Foo myFoo; public event EventHandler FooEvent; public Foo() { myFoo = this; } public void FooMethod() { MemoryLeaksHere memLeak = new MemoryLeaksHere(); memLeak.TryQuit(); } public void FireEvent() { FooEvent(null, null); } static void Main(string[] args) { Foo foo = new Foo(); for (int i = 0; i < 5; ++i) { foo.FooMethod(); } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); Console.WriteLine(“Check memory leak here.”); } } /// <summary> /// This object will cause memory leak /// </summary> public class MemoryLeaksHere { public MemoryLeaksHere() { Foo.myFoo.FooEvent += new EventHandler(OnMyFooEventFired); Console.WriteLine(“\nObject-{0}: Construct. Subscribe.”, this.GetHashCode()); } ~MemoryLeaksHere() { Console.WriteLine(“Object-{0}: Deconstruct.”, this.GetHashCode()); } public void TryQuit() { Console.Write(“Object-{0}: leak me?”, this.GetHashCode()); string input = Console.ReadLine(); if (string.Equals(input, “no”)) { Foo.myFoo.FooEvent -= new EventHandler(OnMyFooEventFired); Console.WriteLine(“Object-{0}: Unsubscribe.”, this.GetHashCode()); } else { Console.WriteLine(“Object-{0}: Not Unsubscribe”, this.GetHashCode()); } } private void OnMyFooEventFired(object sender, EventArgs e) { // Do something } } }

In MemoryLeaksHere object’s constructor, Foo starts to hold a reference to MemoryLeaksHere by registering event handler. In MemoryLeaksHere.TryQuit(), if we don’t unregister, memory leak will happen.

To be more intuitive, you can copy/paste sample code to VS2008, and then enable unmanged code debugging by following:

Project->Properties->Debug->Enable Unmanaged Code debugging

Now set a breakpoint at “Check memory leak here”, and start build/debug. When being asked leak me or not, you can choose either yes or no. For example:

Here, looks like we leak two of them. Finally app will hit the breakpoint and stop. At this point, we can go to VS immedate window to load sos.dll, and then check how many objects in the heap:

!load sos.dll extension C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\sos.dll loaded !dumpheap -type MemoryLeaksHere PDB symbol for mscorwks.dll not loaded Address MT Size 0132e7d0 00983104 12 0132eba0 00983104 12 total 2 objects Statistics: MT Count TotalSize Class Name 00983104 2 24 MemoryLeakSample.MemoryLeaksHere Total 2 objects

So now we know there are two object instances are not recycled. Why are they not GC-ed? Because someone has a reference to them. Choose one of them, and use gcroot command.

!gcroot 0132e7d0 Note: Roots found on stacks may be false positives. Run “!help gcroot” for more info. Error during command: Warning. Extension is using a callback which Visual Studio does not implement. Scan Thread 7592 OSTHread 1da8 ESP:12f434:Root:01312d48(MemoryLeakSample.Foo)-> 0132f704(System.EventHandler)-> 0132f6ec(System.Object[])-> 0132e7dc(System.EventHandler)-> 0132e7d0(MemoryLeakSample.MemoryLeaksHere) Scan Thread 4704 OSTHread 1260

Now we can see that MemoryLeakSample.Foo is still referencing MemoryLeakSample.MemoryLeaksHere via event handler. If it is not 5 iterations, image what would happen if every incoming request results in a slice of memory leak… Soon or later, you online service will be down.

See also:

http://www.codeproject.com/KB/dotnet/Memory_Leak_Detection.aspx

http://blogs.msdn.com/jgoldb/archive/2008/02/04/finding-memory-leaks-in-wpf-based-applications.aspx

http://blogs.msdn.com/calvin_hsia/archive/2008/04/11/8381838.aspx

http://www.automatedqa.com/techpapers/net_allocation_profiler.asp

http://blogs.msdn.com/greg_schechter/archive/2004/05/27/143605.aspx

In my MSDN blog, I need “Recent Posts”, but I don’t need archive side bar. After having played with template for a while, still no luck. Hmmm, looks like I have to DIY it. Fortunately in News sidebar, you can fill in raw html including JavaScript. Then next question is where we can retrieve post tiles. The immediate idea is from current DOM document. Through experiments, I found this is impossible because the DOM is not fully loaded yet when the script is executed. Later, I figured it out that all posts title can be gotten from RSS. For my blog, the address is http://blogs.msdn.com/bali_msft/rss.xml. One thing worth noticing is the fact that RSS in MSDN blog is not up to date – Your post will not instantly appear in the RSS. After I get all posts in RSS format, things became much easier. And then I go ahead to add more interesting things:

• Posts background use two colors in turn
• Show a new tag for posts less than 3 days old
• Show latest 8 posts only
• Show posts’ age

So, the final thing will look like this:

If you find it is useful, feel free to paste below code to you blog’s news section. Note to customize “Configurable params” to your own needs and leave other code intact. It works well at least in my IE 8 and Firefox 3.0.6.

<div id=”RecentPosts”></div> <Script> // Configurable params var recentPostNumber = 8; var rssUrl = “http://blogs.msdn.com/bali_msft/rss.xml”; var title = “My Recent Posts”; var newPostAgeInHour = 72; // Cacluate age of one post. It is all about getting time span in Javascript // return formate: x min; x hour y min, x day y min, x days, x yeas (ago) // Refer to: http://www.w3schools.com/jsref/jsref_obj_date.asp function calculateAge(postDate) { var ret = “fresh!”; CurrentDate = new Date(); TimeSpan = new Date(CurrentDate – postDate); var mySpanArray = new Array(); mySpanArray[0] = TimeSpan.getUTCFullYear()-1970; mySpanArray[1] = TimeSpan.getUTCMonth(); mySpanArray[2] = TimeSpan.getUTCDate()-1; mySpanArray[3] = TimeSpan.getUTCHours(); mySpanArray[4] = TimeSpan.getUTCMinutes(); var TimeSpanTagArray_1 = new Array(“years”, “months”, “days”, “hours”, “minutes”); var TimeSpanTagArray_2 = new Array(“year”, “month”, “day”, “hour”, “minute”); // Starting from non-zero element and pick two significant values for(i = 0; i < mySpanArray.length; i++) { if(mySpanArray[i] != 0) { var correctTag = (mySpanArray[i] == 1)?(TimeSpanTagArray_2[i]):(TimeSpanTagArray_1[i]); ret = mySpanArray[i] + ” “ + correctTag; if(i+1 < mySpanArray.length && mySpanArray[i+1] != 0) { correctTag = (mySpanArray[i+1] == 1)?(TimeSpanTagArray_2[i+1]):(TimeSpanTagArray_1[i+1]); ret = ret + “, “ + mySpanArray[i+1] + ” “ + correctTag; } break; } } return ret; } // Display the recent posts // Refer to: // http://www.w3schools.com/DOM/dom_node.asp // http://www.w3schools.com/DOM/dom_methods.asp function displayPosts (xmldoc) { var newTag = “<SPAN style=\”COLOR: red\”>(New!)</SPAN>”; var posts = xmldoc.getElementsByTagName(“item”); var displayText = “<h3>” + title + “</h3><UL>”; if (posts.length < recentPostNumber) { recentPostNumber = posts.length; } for(var i = 0; i < recentPostNumber; i++) { PostTitle = posts[i].firstChild.firstChild.nodeValue; PostLink = posts[i].firstChild.nextSibling.firstChild.nodeValue; PostDateStr = posts[i].firstChild.nextSibling.nextSibling.firstChild.nodeValue; PostDate = new Date(PostDateStr); CurrentDate = new Date(); // Calculate age var _PostAge = calculateAge(PostDate); var PostAge = “<SPAN style=\”font-size: 80%; color: black\”> (“ +_PostAge + ” ago)</SPAN>”; // Show a new tag for posts happening last days defined by ‘newPostAgeInHour’ var myNewTag = “”; if((CurrentDate.getTime() – PostDate.getTime())/1000/60 < newPostAgeInHour * 60) { myNewTag = newTag; } // Get background color var BKColor = (i%2 == 0)?(“#B8CCE4″):(“#DBE5F1″); displayText = displayText + “<LI style=\”background-color:” + BKColor + “\”><A href=\”" + PostLink + “\”>” + myNewTag + PostTitle + PostAge + “</A></LI>” } displayText = displayText + “</UL>”; var target = document.getElementById(“RecentPosts”); target.innerHTML=displayText; } // Call back function complete(){ if (req.readyState == 4) { if (req.status == 200) { displayPosts (req.responseXML); } } } // Initial async call function getPosts() { if (window.XMLHttpRequest) { req = new XMLHttpRequest(); }else if (window.ActiveXObject) { req = new ActiveXObject(“Microsoft.XMLHTTP”); } if(req){ req.open(“GET”, rssUrl, true); req.onreadystatechange = complete; req.send(null); } } // Entry point getPosts(); </Script>