Conference hydra::amiga_v1

We have an RZ?? running on a 1000 here in the plant. It works fine.
This drive is one of the scsi drives that DEC carries. I believe
the model we are using is 105meg,and came out of a Vaxstation.    
	The IDE drives use the I** standard disk controller,and
I don't know if they can be used with any other controllers. They
are most often much cheaper than the SCSI drives,but I think 
performance is not as good. When we ordered the Decstation I have
to use at work I made sure we got the SCSI interface. The mention
you made of possible incompatability problem surly refered to the
IDE interfaced drives. I'll talk to some of the MSDos users here 
to see what else I can find out. As I spend time in the clone world
I cannot help but wonder what the big deal is all about. the system 
is fast,but then again it is 32 bit,and I can't do any graphics yet.
							bill
    
    

    
    
    	"Are there different flavours of SCSI ? "
    
    YES, there is SCSI I and SCSI II. If the disk is SCSI I then they need
    to support CCS ( common command set ). Most Amiga SCSI controllers
    should handle both. DEC workstations, disks, CDROM, and Tapes follow
    SCSI II.
    
    	The only IDE controller for the AMIGA is a GVP 68030 board. The
    on-board disk controller supports 2 IDE drives. GVP sells a 40 or 80
    MB quantum IDE disk.
    
    		Steve Peters
    

    
    Thanks Steve and Bill.
    
    Re: .1    Does your reference to RZ  imply that the PC4X4 disks used in the
    workstations  are just standard RZ SCSI disks with a different part
    name.  The DECdirect page 42 not on incompatibility referred to in .0
    doesnt state
    
    Re: .2   The 68030 GVP board with IDE controller is unfortunately out
    of my price range. In fact, a colleague of mine picked up an employee
    purchase refurbished 80386 DECstation 316 with 8MB memory and 40MB hard disk
    the other day for $1100, so I think we'd all better be a bit careful
    about overcapitalising on our Amy's -  hence my looking for the cheap
    disk  option. 
    
    If any one else has any more info on IDE interfaces or what the PC4X4
    disks really are that will be great.
    
    Randall King, Sydney
    
    
    
    
    
    
    Randall King,
    Sydney

    
    Typo correction. In left off the sentence ending:
    
    The DECdirect catalog page 42 note on "incompatibility" referred to in
    .0 doesn't indicate whether the caution is with the IDE  or
    SCSI.   If anyone knows what this caution is meant to mean, that would be
    great.

    Re: last few
    
    If I'm not mistaking, the IDE controller is also referred to as
    "AT-Controller". If so, the A2091 and A590 also provide one IDE port in
    addition to their SCSI port.
    
    Regards,
    
    <CB>

    
    What is the difference between the two SCSI's ??
    
    I have just seen an artical in Popular Computing Weekly...re 
    Golem (in the U.S.) otherwise know as Kupke Computertechnik (a West
    German Co.) has just shown and now shipping a SCSI II hard disk
    controller for $199 (Tel No 01-049-231-818325 this is the German tel no
    from England...)
    

    SCSI II is faster and more powerful than SCSI I.
    It has a larger defined command set, whereas SCSI I's numerous commands
    are largely optional (meaning a controller/device doesn't need to
    support more than a fewbasic commands).
    SCSI II is designed to be faster, and it can also be used in "Wide" or
    "Fast" options. SCSI II Fast is REALLY fast. SCSI II Wide supports
    word, and I believe Long Word data transfer. (If I'm worng on the long
    word xfer, someone tell me). I wouldn't invest too heavily in SCSI II
    right now... It is a not yet finished standard yet: most/all of the
    protocol/electrical specs are done, but many of the physical/cabling
    specs are still under discussion. Conventions have been developed in
    the mean time, but for instance open ended SCSI II has no connectors
    defined in specs. Besides, SCSI III has been under development for
    quite some time now.
    
    					bob
    					REFINE::POMEROY
    
    

No, DECstations (PC type) don't use RZxx disks. I do believe they are SCSI
though. I think the reasoning was to by a complete system from Tandy and
not have to qualify the disk subsystem.


SCSI II does support a 32bit bus. So max transfer rates:

	8 bit "slow" (scsi I)	5MB/s
	8 bit fast		10MB/s
	16bit fast		20MB/s
	32bit fast		40MB/s   !! 

I think fast requires (or at least recommends) differential bus transcievers.

Re: -2 or so,

is the imbedded controller in the A590 actually compatible with IDE drives ?

Mike

    Re .9:
    
>   is the imbedded controller in the A590 actually compatible with IDE
>   drives?
    
    The 20MB drive that comes with the A590 turns out to be an "XT" drive
    (8-bit data path) using a 40-pin IDC connector.  There exist XT-to-IDE
    interfaces to support IDE drives from XT controllers, so I suppose you
    could do likewise if you so desired.  I don't think there would be any
    price or performance benefit to doing so, however.  3.5" SCSI drives,
    such as the Quantum 105S fit very nicely in the A590 and provide
    excellent performance.  (They're also getting cheaper of late. 8^)

    My prefered path is a SCSI drive either in addition to the existing WD
    drive in the A590 or placing it externally. I was just checking my
    options as it seems the IDE style drives are still a bit cheaper than
    a SCSI equivalent.
    
    Thanks
    	Mike