Too frequent update of Symantec Endpoint Protection in Mac

I have installed Symantec Endpoint Protection (SEP) for Mac in an unmanaged mode. The problem is its LiveUpdate runs too frequently and I can't disable it or modify. Although it provides Symantec Scheduler UI, it doesn't look like working at the beginning.

It turns out SEP installs a default schedule owned by a root user, which a normal user can't see in his/her Symantec Scheduler UI. A solution is as follows:

1. Open a terminal

2. Type sudo symsched -d all

3. Setup a new schedule by using Symantec Scheduler UI or a command like,

symsched LiveUpdate "Update All Daily" 1 1 -daily 13:00 "All Products" -quiet

Reference:

http://www.symantec.com/connect/forums/sep-mac-live-update-bouncing-dock

http://www.symantec.com/business/support/index?page=content&id=TECH134203&locale=en_US

http://www.symantec.com/business/support/index?page=content&id=TECH105502

Time measurement methods

I've just recently tried to decide what is the best way to measure times. The followings are a short summary I got after browsing a few sources in the Internet (See references).

1. gettimeofday

-. Resolution : 1 microsecond

-. Have a negative time issue due to clock reset or NTP

2. clock_gettime(CLOCK_MONOTONIC)

-. Resolution : 1 nanosecond

-. Use HPET, an external chipset on board.

-. An optimal choice, considering both reliability and portability

3. RDTSC

-. Resolution : 1 nanosecond

-. Use RDTSC, a cpu instruction

-. Very light-weight but lots of issues on reliability

-. For a short run and if it is clear on the reliability issues (see Ref 2.), it's good to use.

References:
1. http://aufather.wordpress.com/2010/09/08/high-performance-time-measuremen-in-linux/
2. http://juliusdavies.ca/posix_clocks/clock_realtime_linux_faq.html

3. http://www.kerrywong.com/2009/05/28/timing-methods-in-c-under-linux/

HDF5 MPIIO's Hyperslab_by_chunk.c error in Mac

In Mac, I got a runtime error after compiling hyperslab's chunk example, Hyperslab_by_chunk.c

As mentioned in here, the error is Mac-specific but the solution what I found is a little different.

Use

hdf5_cv_mpi_complex_derived_datatype_works='no',

instead of

hdf5_mpi_complex_derived_datatype_works='no'

I have tested with HDF5 version 1.8.5.

A few useful Windows HPC commands

0. Set Default scheduler

set CCP_SCHEDULER=headnode_name

1. clusrun

One can run the following command from his desktop to setup compute node environments

clusrun /user:domain\username dir

clusrun /user:domain\username xcopy \\headnode_name\dir .

clusrun /user:domain\username setx PATH "somepath"

2. job

job list /scheduler:headnode_name

3. node

node list /scheduler:headnode_name

5. cluscfg

cluscfg setcreds

More details are available at http://technet.microsoft.com/en-us/library/cc972841(WS.10).aspx

Imporve serialize() in R for windows

serialize() function of R is very slow in Windows. My observation is that calling realloc is the bottle neck. The workaround can be replacing realloc with Rm_realloc in $R_HOME/src/main/serialize.c. More specifically, I have updated as follows:

1. In function, resize_buffer(...), replace

mb->buf = realloc(mb->buf, newsize);

with

mb->buf = Rm_realloc(mb->buf, newsize);

2. In function, free_mem_buffer(...), replace

free(buf);

with

Rm_free(buf);

Directions for compiling R in Windows are in http://cran.r-project.org/bin/windows/base/rw-FAQ.html#How-can-I-compile-R-from-source_003f

The following is a short result running on my Windows 7 desktop:

The original:

> system.time(serialize(matrix(0, 1000, 1000), NULL))

user system elapsed

5.74 4.39 10.15

> system.time(serialize(matrix(0, 2000, 2000), NULL))

user system elapsed

85.40 74.80 161.62

After updating:

> system.time(serialize(matrix(0, 1000, 1000), NULL))

user system elapsed

0.78 0.30 1.10

> system.time(serialize(matrix(0, 2000, 2000), NULL))

user system elapsed

6.21 4.13 10.54

Compile Rmpi with Windows MPI (HPC pack)

Compile Rmpi (http://www.stats.uwo.ca/faculty/yu/Rmpi/) in Windows

1. Install HPC Pack 2008 SDK with SP1 and modify line 314 in mpi.h (installed_dir\Include) as follows:

//typedef __int64 MPI_Offset;

typedef long long MPI_Offset;

2. Download Rmpi from http://www.stats.uwo.ca/faculty/yu/Rmpi/download/linux/Rmpi_0.5-7.tar.gz

3. Untar the source and modify src/Makevars.win by changing directory and library option (-lmsmpi) as follows:

PKG_CFLAGS = -I"C:\Program Files\Microsoft HPC Pack 2008 SDK\Include" -DMPI2 -DWin32

PKG_LIBS = -L"C:\Program Files\Microsoft HPC Pack 2008 SDK\Lib\i386" -lmsmpi

4. Compile and install

R CMD INSTALL Rmpi

5. Build for re-distribution

R CMD build --binary Rmpi

Setting up a non-admin SVN repository shared with multiple users

A trick is using SSH with public key as described in

http://svn.collab.net/repos/svn/trunk/notes/ssh-tricks

As a quick summary, I have set up a SVN repository as follows:

1. create a svn root directory, which will share with others, and create a repository:

$ mkdir /path/svnshare

$ svnadmin create /path/svnshare/project

2. Get public keys of user to share svn repository and insert to ~/.ssh/authorized_keys the following line:

command="/path/to/svnserve -t -r /path/svnshare --tunnel-user=[USERID]",no-port-forwarding,no-agent-forwarding,no-X11-forwarding,no-pty [KEY_TYPE] [PUB_KEY] [COMMENT]

[.] should be replaced with users' information

3. Now users can access the shared svn repository remotely as follows:

svn co svn+ssh://[MYID]@[SERVER IP or DNS]/project

Note that use relative path names of repository after server ip or dns