Code Development on NT Some notes on experience gained in developing cross-platform (NT/Unix) HEP software for the Linear Collider Detector More of a Random Walk than a Formal Overview of Development Tools HEP-NT workshop SLAC - October 1999 Tony Johnson Tony Waite* * In absentia

NT Code Development l Topics –NT Code development tools for C++/Fortran/Java –Code development issues –Code management SourceSafe CVS DEC - –Using NT as a data server –Conclusions

Windows NT Development Tools l For windows only development, tools are excellent: –Visual C++/J++ (MS Java)/Compaq Fortran Excellent IDE allows development in all three languages –Integrated editor, cross-language debugger –Integrated build tool (make clone) –Incremental linker (that works) –Integrated code management (visual sourcesafe) –Object browser –SLAC has site license for MS developer tools

C++ for cross platform development l Cross Platform C++ development has many problems –Makefile for each platform Need to build/debug on each platform Versionitis –External dependencies –Compiler flags Even egcs compiler has many system specific flags –Different methods for building DLL’s/C++ name mangling –Compiler bugs –Differing Levels of ANSI/STL Support –Architecture specific bugs Found bugs in both Visual C++ (5.0) and egcs compiler for intel.

C++ for cross-platform development l Certainly possible - Simulation package does work on both NT and Unix. Large amount of time goes into testing/debugging on different platforms.

Java for Cross Platform Development l Have succeeded in writing entire reconstruction/analysis package in Java l Currently using Visual J++/Sourcesafe –All development currently being done on NT –JAR files built on NT and put on web server for download by others. l Java code can be run –Standalone from command prompt/batch job –Inside Java Analysis Studio (JAS)

Java Analysis Studio l Cross Platform Java GUI for data analysis

Java for cross-platform Graphics/GUI

Java Experience l Write Once Run Anywhere –Really works (for applications, if not applets). –Develop on NT, runs without changes elsewhere l Developers have been able to learn language and tools and get up-to-speed fast l Performance - Adequate, getting better all the time l Need to abandon Visual J++, Source Safe

CVS for cross platform development l CVS is available for NT as well as Unix l NT tools include: –line mode tools –WinCVS Rather confusing GUI –jCVS Cross platform CVS GUI written in Java Doesn’t support ssh access to remote repository? l Several tools available for web based access to code –CVSWeb - perl script –jCVS servlet - works well on NT

jCVS Client

jCVS Servlet

CVS security issues l Supports distributed access to code repository –bewildering array of access methods/security issues rsh - no longer allowed at SLAC pserver - –needs custom server, –passes weakly encrypted passwords over network ssh –doesn’t work with all CVS clients –complex to set up client –no AFS token support

CVS vs. Sourcesafe

Is CVS sufficient for a physics collaboration? l If using Java - probably l If using C++, not really, –Need to be able to switch between configurations easily Logical names where are you? –Location of external dependencies –Would like to use pre-built dll’s where possible. –Want to isolate users from system dependencies as far as possible. –Want to avoid “nightly builds” l Need to layer tool on top of CVS, make –LCD Solution: Development Environment Controller (DEC)

Development Environment Controller l Written for LCD by Tony Waite, could be used by others –Hides details of file organization from user User deals with subsystems, Gismo, Recon, etc. Easy to switch between PROD,DEV,Test version of each subsystem User Profiles allow saving/restoring environment. –Hides machine dependencies of BUILD operation Automatically archives CVS version numbers for production BUILD’s

Running a (Java) Data Server on NT l Use NT Service Manager to Run Data Server –Microsoft Java has built-in support for running as NT server Application can be distributed as a single.exe which installs itself as an NT service –Other Java implementations can be run as an NT service with 3rd party add-ons (or roll your own). l Error logging using NT event log/viewer Desktop Client Network Data Server DIM Remote Data

NT Service - Pros and Cons l Pros –Auto start on reboot –Runs in background –Use service manager to start/stop service l Real life problems –Does not auto restart Application can unexpectedly pop up dialog box! –Remote control difficult Remote Server Manager only distributed with NT server (or with NT resource kit). Requires port 137/138 access (blocked at SLAC firewall) or VPN/PPTP

Net Meeting for Remote Control l Netmeeting 3.0 has “Remote Desktop Feature” –If run on server allows remote access to server desktop from any NT/95/98 machine. –Free! l Security –Claims to use encrypted communication channel –Requires NT login to access remote desktop –Security dubious l Potentially very useful, perhaps worth considering

NT Disk Cache Problem l Problem with reading large datasets –NT will grow disk cache until it takes 99.5% of physical memory, regardless of who/what else requires memory. –Reading large datasets can result in NT totally grinding to a halt. –No system parameter to limit disk cache size l Workarounds –If you have access to call to C open statement you can turn off disk caching (big if) –Can run program which constantly flushes disk cache l Conclusion –NT not ready for primetime data server applications –Windows 2000 better?

Things I didn’t talk about l Because I don’t know anything about them –Sniff+ - Cross platform IDE –Cross platform GUI development with C++ QT Widgets – –Libtool/configure NT ports exist but not for non-experts –cygwin Unix environment under NT

Conclusions l Tools for code development under NT only are great –Development tools probably better than Unix l Cross platform development –In C++ is a lot of extra work –Java can make things much easier, especially for: GUI applications Client/Server applications l NT for HEP batch/server side data processing –No obvious advantage over Unix/Linux –Tools and OS not as well suited to task as Unix l NT still maintains lead as desktop machine –Unix seems to be catching up fast (gnome, * office)