C90/DMF - Interface with HPSS
- hack PD ftp code and patch in
- Handling all exceptional cases
- Can't test all contingencies
- Not flexible
- Not enough time for robust code
- fork/exec ftp/hsi session
- Buffering is a problem
- No immediate feed-back
- Need hacked ftp to force line buffering
- Else use pseudo-tty mechanism
- Use expect (Tcl add-on)
- Designed for fronting interactive sessions
- Uses pseudo_tty
- Known scripting language & heavily documented
- "Talks" between two interactive programs