Info Request - SCSI vs. ESDI

[barry.s.kizmann]

This is the first time I am posting to this group, so I hope it is the correct
one.  I have a question about SCSI vs. ESDI.  A friend of mine just acquired
a Data General AViiON 5000 Unix Server.  He has to decide whether to use
ESDI, SCSI or both drives.  It will be the same drive for either controller so
seek time, rotational latency, and head transfer rate don't matter.  They both
also use the same VME bus.  

The following describes the ESDI:
    VME/ESDI Controller (equivalent to the Ciprico RimFire 3400)
    National 8466 Disk Data Controller Burst rates w/disk of up to 2.5Mb/sec
    3ms controller overhead w/80186 processor
    Segmented read-ahead Cache (512Kb)
    Reduced latency operations

The following describes the SCSI:
    VME/SCSI Host Adaptor (equivalent to the Ciprico Rimfire 3513)
    Synchronous and Async modes through WD 33C92 chip supporting 5Mb/sec 
        and 1.5Mb/sec respectively
    3ms controller overhead w/80186 processor

Each one also has:
    Overlapped seekds
    Command Queueing for each unit in 64Kb memory
    Command Optimization
    Command Coalescing
    Scatter/Gather operations

He has two drives and in the future may be getting a third.  His applications
are written in COBOL and use some type of ISAM layout, so he expects to be
doing lots of transfers of small records.  The applications are typical of a
small business, payroll, billing, customer info, etc.

Does anyone have any insight to what combination to get, or does it even matter.

Greg Romer    romer at csd5.nyu.edu or romer at spunky.cs.nyu.edu