[comp.sys.sun] SBus to VME converter

tep@tots.Logicon.COM (Tom Perrine) (11/01/90)

Several weeks ago, I asked for information on comp.sys.sun (and other
places) from anyone currently using an S-BUS to VME converter.

I got two replies, one asking for any information *I* got, and the other
informing me of some S-BUS I/O products. I have also seen at least two
other requests on sun-spots/comp.sys.sun and other lists asking about such
products.

Since no one *on the net* seems to have experience with these product yet,
I will relate what I have been able to find out.

We have deferred our purchase of S-BUS to VME converters until after the
new year, so I currently have no first-hand experience with such products.
However, I can report that the converter made by Bit3 seems to be making
customers happy. (As near as I can tell, this is the only converter
currently shipping.)

After talking to Bit3's technical support, I have pieced together the
following information about their product (SBus-A32/D32 VME Adapter):

The converter consists of a single-width S-BUS card, a 6U VME card and a
shielded cable (lengths of 8', 25' standard, or 300' with a long line
driver).

Basically, this device allows VME memory to appear exactly as if it were
SBus memory, with the additional capability of converting VME interrupts
into SBus interrupts. There is also a programmable interrupt that can be
initiated from the SBus into the VME bus.

Bit3 claims that if you already have a Sun-4/SPARC VME device driver for
your VME device, that there are *no device driver changes required* to use
the device and driver on a SPARCstation! Apparently, between the memory
mapping and the interrupt mapping, the (VME) driver cannot tell that there
is an SBus present.

Bit3 was very helpful in providing names of current customers and
references. The customers we talked to were happy with the product.
(Maybe we should have asked for names of dissatisfied customers? :-) Some
users had just used the stock VME driver they already had (such as from a
SPARCserver 4/330), others had written a new device driver.

Disclaimer: We have not purchased or tested this product; we have no
relationship with Bit3 other than as a prospective customer. Logicon has
no idea what I'm doing anyway, and would deny it if they did.

Bit3 can be reached at:
	Bit3
	8120 Penn Avenue South
	Minneapolis, MN 55431-1393
	(612)881-6955    Telex 4997016:BITTHRE
	FAX (612)881-9674

They have no network address.

Happy SBusing!

Tom Perrine (tep)                       |Internet: tep@tots.Logicon.COM
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