Logic and Protocol Analyzers

At last year's OLS, talking to people about PCI bus behaviors exposed a surprising gap in awareness of tools to observe those behaviors. Access to logic analyzers has enabled me as a kernel developer to debug and learn HW behaviours. I will share what I've learned using a HP 16500 series analyzer for SCSI and PCI SW work.

Oscilloscopes, logic analyzers, and protocol analyzers give different views of events on the underlying HW. The basic capabilities of a logic analyzer are to collect a history (with coarse granularity) of signal state. Setting up a logic analyzer can provide challenges; usually by limitations of the target platform or specific configuration. Using a logic analyzer for SCSI or PCI debugging can be tricky depending on the problem being debugged and the number of states the analyzer can store.