Technical Areas of Expertise

John V. Levy, Ph.D.

Computer Architecture

System Architecture
Interfaces & protocols for inter-module communications [Stanford, DEC]

CPU – Instruction set design & interpreters
Pascal p-machine implementation [Apple] FORK – JOIN instructions for multi-processor systems [Stanford] On-chip micro-code in 80286 [consulting client]

Multi-processor systems
Multiple microprocessor system [Stanford] Hundreds of processors system [Tandem]

Bus design for Processor-Memory-I/O
“VAX-SBI” backplane bus [DEC] Interconnect for hundreds of processors [Tandem]

I/O Channels
“Massbus” disk & tape channel [DEC] Serial I/O buses – CI & BI concepts[DEC]

Hard Disk attachment buses
Ultra-ATA/33, 66, 100, 133 [Quantum, Intel] Ultra-SCSI [Quantum]

Local Area Networks (LANs)
Low-cost LAN with passive transformer coupling [Apple]

Memory module design [DEC]
Concurrency
Cache

Software Development

Real-time data acquisition using re-entrant code [SLAC, Stanford] Discrete-event simulator development [Stanford, Quantum] Embedded systems software [Quantum]
Hard disk drive control firmware
Hard disk drive internal self-test & monitoring
Testing tools (hardware & software) for firmware validation

Management of software & firmware development
Project management [DEC, Apple, Quantum] Organization [DEC, consulting clients] Methodology & tools [consulting clients, Quantum] Management issues [consulting clients, Quantum]

Operating systems

Real-time dedicated data acquisition system [SLAC, Stanford]
Interrupts, re-entrant code, queued events, response deadlines Real-time & batch OS with time-sharing overlay

RSX-11D & IAS operating systems [DEC]
Real-time & batch OS with time-sharing overlay

File system design for write-once optical storage [Ricoh]
I/O management
Data compression on hard disk drives [Quantum] Interaction of caching with hard disk I/O drivers [Quantum, Microsoft] I/O management using packetized control messages [DEC]

DOS internals [consulting client]
File system space allocation
Keyboard management

Multimedia streams

IEEE P1394 “FireWire” “I-Link” standards [Quantum]
1394 Trade Association – AV Working Group [Quantum, Sony]
Design of commands & control messages for stream recording & playback on hard disk drives
Standards for control of AV equipment on 1394/FireWire bus

Performance evaluation & measurement

Simulation of multiple microprocessor system [Stanford]
Trace-driven simulation of hard disk performance (analysis & prediction) [Quantum]
Benchmark analysis [Quantum]

Database systems

Rollback recovery in distributed databases [Tandem]
“Caching” – Differential database [Tandem]