Welcome to my home page!

I work (primarily) on the Control Program (CP) in the Connectivity area. This includes ISFC (Inter System Facility for Communication), and more recently has expanded to include Virtual Channel-to-Channel (VCTC) and Virtual Network Interface Card (NIC) support. Virtual NIC support (which began as part of VMLAN or Guest LAN support) is now known as VSWITCH support.

The following links are intended to supplement (not replace) the official IBM publications.

• VM Guest LAN support in z/VM.
• Virtual CTCA (VCTC) support in z/VM.

Professional Background

• I earned a B.S. in Computer Science at North Carolina State University (NCSU-Raleigh).
• I worked as an application programmer for Burroughs Wellcome Co at Research Triangle Park, North Carolina. My job involved design and implementation of application programs to support the analysis of their research data. Most of these applications were written in PL/I (with an occasional FORTRAN program).
• In 1981, I joined IBM to work in CP Development at Endicott, New York. Most of my projects have involved I/O device support or simulation. For example, I worked with two other developers to write support for the printers that were added in VM/SP Release 3 (this was back before "Version" became significant). Most of my programming is done in Assembler Language.
• For VM/ESA Version 2, Release 1.0 I was responsible for redesigning the Virtual CTCA simulation in CP to more closely emulate the hardware and to improve performance.
• For z/VM Version 4, Release 2.0 I worked with a small development team to create a fully simulated network adapter providing connectivity between Linux guests on the same CP host. This early virtual NIC support made it possible for Linux users on z/VM to communicate with each other (within the LPAR) using a network interface instead of multiple peer-to-peer (IUCV or CTCA) connections.

  This was released as Guest LAN support. It was my privilege to describe this early virtual NIC support at the Europe zSeries Technical Conference 2002 in La Hulpe, Belgium (Session V210: Using VM Guest LAN Support).

• For z/VM Version 5, my primary focus was improving and enhancing our virtual networking capabilities. I was part of the team that designed and implemented our z/VM support for VSWITCH, IEEE VLAN, and OSA Express Layer 2 transport.
• For z/VM Version 6, my primary focus was improving our ISFC (Inter-System Communication Facility) capability. I was part of the team that designed and implemented ISFC link protocol changes to improve the throughput of the ISFC link and to spread the ISFC traffic across multiple physical CTCA links to satisfy the requirements of an SSI cluster.
• For z/VM Version 7, my primary focus was on enhancing VSWITCH support to exploit the Network Express (OSH) adapter as an uplink device (connecting VSWITCH guests to the external network whether they coupled to the VSWITCH via QDIO or EQDIO virtual devices.)

You can reach me at: musselwh@us.ibm.com

The information provided, and views expressed on this site are my own and do not represent the IBM Corporation.