Few days ago, I was investigating why one of our servers in cloud stops responding. Basically, it was so bad that we have to force restart server. After some investigation I found that there is IIS server that processes requests and some requests starts external application. And in certain situations, this process starts to allocate a lot of non-paged pool memory. About 100 megabytes per second.

Non-paged pool is special type of memory that is never paged out to disk. It is must be non-paged because at certain times of processing requests paging is unavailable. For example, when interrupt is processing. Also, for example disk driver structures should be non-paged because obviously they cannot be paged out. And in general,

Few days ago, my friend asked me to check iPad as it does not charge and does not work well. And today I got time to check.

Initially, I found that it does charge, it was discharged and displayed picture with battery. And as result it just take as lot of time to charge as it charges very slowly as there is pretty much no software control over charge current, duration etc. Honestly Apple can do better to put some text on that screen that explains what’s going on.

After it did charge it starts but showing famous Connect to iTunes picture. Ok, iTunes time. iTunes told me that I have to either Update it or Restore. Initially I did

Recently I was investigating deadlock related to COM in .NET. In we have some engine that executes asynchronous requests. It is written in native code and use COM like interfaces. Nothing like true COM where you have some registration etc. We just use COM like interfaces for interop between .NET and native code. And I have following code:

00 00000001`4eeed7d8 00007ff9`184b8027 ntdll!NtWaitForMultipleObjects+0x14
01 00000001`4eeed7e0 00007ff9`1a583905 KERNELBASE!WaitForMultipleObjectsEx+0x107
02 00000001`4eeedae0 00007ff9`1a583665 combase!MTAThreadWaitForCall+0x115
03 00000001`4eeedbb0 00007ff9`1a5329c7 combase!MTAThreadDispatchCrossApartmentCall+0xc5
04 (Inline Function) --------`-------- combase!CSyncClientCall::SwitchAptAndDispatchCall+0x325
05 00000001`4eeedc00 00007ff9`1a581e94 combase!CSyncClientCall::SendReceive2+0x407
06 (Inline Function) --------`-------- combase!SyncClientCallRetryContext::SendReceiveWithRetry+0x25
07 (Inline Function) --------`-------- combase!CSyncClientCall::SendReceiveInRetryContext+0x25
08 00000001`4eeede00 00007ff9`1a530900 combase!DefaultSendReceive+0x64
09 00000001`4eeede60 00007ff9`1a581bc4 combase!CSyncClientCall::SendReceive+0x330
0a 00000001`4eeee090 00007ff9`1a5a2e4e combase!CClientChannel::SendReceive+0x84
0b 00000001`4eeee100 00007ff9`1b1d8b95 combase!NdrExtpProxySendReceive+0x4e
0c 00000001`4eeee130 00007ff9`1a5a0cbb rpcrt4!NdrpClientCall3+0x395
0d 00000001`4eeee490 00007ff9`1a61c5f2 combase!ObjectStublessClient+0x13b
0e 00000001`4eeee820 00007ff9`1a5268a9 combase!ObjectStubless+0x42
0f 00000001`4eeee870 00007ff9`1a59cd6f combase!CObjectContext::InternalContextCallback+0x259
10 00000001`4eeee990 00007ff8`c79fed60 combase!CObjectContext::ContextCallback+0x7f
11 00000001`4eeeea30 00007ff8`c79ffb42 clr!CtxEntry::EnterContext+0x295
12 00000001`4eeeec10 00007ff8`c789de97 clr!IUnkEntry::UnmarshalIUnknownForCurrContext+0xbd
13 00000001`4eeeecc0 00007ff8`c789dde2 clr!IUnkEntry::GetIUnknownForCurrContext+0x20cd8f
14 00000001`4eeeecf0 00007ff8`c76924c1 clr!RCW::SafeQueryInterfaceRemoteAware+0x20bab2
15 00000001`4eeeed50 00007ff8`c75f1f79 clr!RCW::CallQueryInterface+0x8d
16 00000001`4eeeedc0 00007ff8`c75f226f clr!RCW::GetComIPForMethodTableFromCache+0xb5
17 00000001`4eeeee80 00007ff8`c75f2716 clr!ComObject::SupportsInterface+0xfe
18 00000001`4eeeeff0 00007ff8`c75f2642 clr!Object::SupportsInterface+0x9e
19 00000001`4eeef060 00007ff8`c75f255a clr!UnmarshalObjectFromInterface+0x7a
1a 00000001`4eeef0a0 00007ff8`69a6a493 clr!StubHelpers::InterfaceMarshaler__ConvertToManaged+0xca
1b 00000001`4eeef240 00007ff8`c74b2e89 0x00007ff8`69a6a493
1c 00000001`4eeef290 00007ff8`c75f13b3 clr!COMToCLRDispatchHelper+0x39
1d 00000001`4eeef2c0 00007ff8`c74b2de7 clr!COMToCLRWorker+0x1b4
1e 00000001`4eeef380 00000001`3aeb49fb clr!GenericComCallStub+0x57
1f 00000001`4eeef410 00000001`3aeb4721 AsyncEngine.AsyncResult.PerformCallback+0x4b

Last time when I wrote about Microsoft Skype, I was quite unhappy about it. But I was expecting that Microsoft will fix eventually all these problems. But unfortunately, not only they didn’t fix it, they made it pretty much unusable for me.

Let me explain my setup. I have home and work computer that running Skype with the same account. My iPhone also has Skype with the same account.

And about 2-3 month ago I found following problem on any of my computer: I typed some text and press Send button. Text disappeared from input text box, but it wasn’t added to list of my messages. If I restarted Skype, then I see that message added to list of