#turning HD off
21 messages in this thread
Bruce,
Thanx for the input! I had thought of using SCSI ID switcher but do
not have the slightest idea where to get any of these beast or what they
would cost. Any ideas?
As far as no power to the drives, wouldn't it act the same as a
removable media drive with no media? I wouldn't power up or down a drive
while the cpu was one.
Thanx,
…steve
Cruising on Autopilot
from beautiful Coastal South Carolina
Steve,
My assumption is that, with the power off, the drive's SCSI drivers wouldn't be
entirely transparent. Maybe I'm assuming the worst but unless I could verify
otherwise, I'd be pessimistic about SCSI bus performance.
As far as putting a SCSI ID remote switch in, you'd have to check out what sort
of switches are used on the drive itself. If the ID is strapped with three
pairs of shorting jumpers, you're in luck. It would be quite easy to extend
this via ribbon cable to a multi-pole switch (aka wafer switch). If your drive
has an encoded switch (one switch, marked 0-7), then your best bet is to have a
clearance hole in the chassis to allow convenient external switching.
Good luck,
___
/__) ,_ _ _
_/__) / /__/ /_ /_-'
PreVue Technologies
Amiga Vendor section #5
Bruce,
Thanx for the responce, I presently have a 105 lps quantem hd, 105 pro
quantem, a sysquest 88 meg removable, and shortly will be replacing the
Pro 105 with a seagate 530 meg and adding a NEC CD-ROM. Possibly in the
very near future (if I can talk my friend out of it) a tamburg tape drive.
The quantems and the sysquest all have the smae tupe of id selection (3
pairs of shorting jumpers) at this time the seagate and cd-rom are unkown.
The purpose of this mod are being able to transport all of my data to
different machines, without the diassembly of all my other components (2
modems, DCTV, monitor, printer, bridgeboard periperals, ect.) ala users
group meetings and the like. With the possible different ID selection
methods it may be easier to do as Erik suggested, switch both +12 and +5v
with dpst switch, although your suggestion is more eloquent (and the
proper way). Any ideas as to who to contact for the id selector switches.
I live in a rural area and the closest city (Charlseton, SC) does not
have anything remotely close. Again I appreciate your input!
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
Steve,
I would imagine that you could walk out of Radio Shack with everything you need
to do the job. Your parts list should look something like this:
1 Encoded, 3-pole rotary switch (BCD NOT preferable) or 3 SPST toggle switches
1 foot ribbon cable, 6 conductor 1 IDC header, 6 position (Insulation
Displacement Connecter, crimp-type)
Added to the above, you'll need some hand tools and soldering gear. Rub-on
labels would make things look much nicer and avoid confusion.
The encoded switch is going to be tough to find, at least one that's
appropriate for your front panel. I often see DIP switches that are BCD
encoded, complete with dial and numbers. Too small for the front panel,
though.
Good luck,
___
/__) ,_ _ _
_/__) / /__/ /_ /_-'
PreVue Technologies
Amiga Vendor section #5
>>1 Encoded, 3-pole rotary switch (BCD NOT preferable) or 3 SPST toggle
>>switches 1 foot ribbon cable, 6 conductor 1 IDC header, 6 position
>>(Insulation Displacement Connecter, crimp-type)
Thanx Bruce, that was the info I needed!
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
> wouldn't it act the same as a removable media drive with no media?
This is about what would happen if you just switched the 12V off. The 5V would
still power the SCSI interface circuitry, and the SCSI address would still be
'active'. This would mean that you could not use that address for another unit.
Switching the 5V off too, would disable the address match.
-larry
Larry,
Good thoughts, come to think of it when there is not a cart in the
sysquest, the ID is still spoken for, so perhaps you are right. This is
the kind of input I was looking for. Bruces idea of a remote scsi id
switch would be ideal, but I have absolutely no idea where to even start
looking, perhaps redmond cables? If I can not find them (remote scsi id
switches) I will try a series of dpst in the front of the case.
I have just started to qet my hands dirty with a little lite hardware
hacking and this is fun (as long as nothing blows up!)
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
A remote SCSI ID switch is quite simple, and as you point out, a few discrete
switches will also do the trick. Try your local electronics distributors, or
perhaps some of the Mac stores.
-larry
The SCSI ID switch is a good idea…..Remember that you'll probably have
to reset the power on the drive to get the ID change to take effect when
you change it. As for availability of those switches, I could swear I saw
rotary DIP switches at Radio Shack, but all they list is the catalog is
the std 4-8 position rocker switch type. (They'd work, but they're not as
nice as the push-button or rotary stylewhich decode the binary digits for
you.)
As for powering the drives down, I've never run into a problem with
leaving unpowered drives on the SCSI chain. The only time you might run
into a problem is if the last drive uses terminating resistor packs, and
the drive is supposed to supply terminator power. (Most newer/bigger
drives have a jumper for this.) My advice is to always use an external
terminator, and set all drives/controllers to supply terminator power to
the bus. (The latter is a recommendation by DEC for it's drives, and is
fairly commonly used.)
Good Luck,
Erik Flom
Erik
>>As for powering the drives down, I've never run into a problem with
>>leaving unpowered drives on the SCSI chain.
Do you remeber if the unpowered drive still occupies the same address if
left onthe chain?
>>The only time you might run into a problem is if the last drive uses
>>terminating resistor packs, and the drive is supposed to supply
>>terminator power
This should be no problem as I have an active terminator that plugs
directly into the last header on the scsi cable. I have just pulled the
terminators off all the drives and the terminator on the cable itself
pulls all the drives up.
Thanx for all the help
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
'Do you remember if the unpowered drive still occupies the same address if
left on the chain?'
Once the computer is rebooted, the drive won't show up is it's not getting
power. (You can even make it disappear w/o rebooting if you use a tool
like SCSIMounter.)
'…I have an active terminator…'
I'm jealous! How much did it set you back? (If I ever had any SCSI
problems, I'd buy one in an instant. Thus far, I've never had a SCSI
problem that didn't turn out to be user error. [knock wood])
Erik Flom
Erik,
I have SCSI Mounter (I own a sysquest and it is almost unusable without
it!)
I got the scsi active terminator from Daniel Wolf 70250,626, a few months
ago for around $30-40 I think. It plugs into a female 50 pin centronics
connector. I have misplaced his address and ph # (I need to send a cable
back to him and don't know where to send it!) Daniel is very helpful,
friendly and Amigawise and carries quality mechandise.
With all the help and info I am getting here all the locals are turning
to me <G> as the local scsi witch doctor! can you imagine that?
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
Steve;
Here is Daniel's address: 1903 Adria Ave.
Santa Maria, Calif.
93454
phone: 1-805-349-1104
Hank
Thanx Hank!
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
Erik,
I have SCSI Mounter (I own a sysquest and it is almost unusable without
it!)
I got the scsi active terminator from Daniel Wolf 70250,626, a few months
ago for around $30-40 I think. It plugs into a female 50 pin centronics
connector. I have misplaced his address and ph # (I need to send a cable
back to him and don't know where to send it!) Daniel is very helpful,
friendly and Amigawise and carries quality mechandise.
With all the help and info I am getting here all the locals are turning
to me <G> as the local scsi witch doctor! can you imagine that?
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
> Do you remeber if the unpowered drive still occupies the same address
> if left onthe chain?
If the 5V is switched off, the address circuitry will not respond, and the
address will be available. If ONLY the 12V is switched off, the address will
not be available because the drive will still respind to it.
-larry
Thanx Larry, that is exactly what I was asking to start with. I will try
the id selector method first if the local radio shack has the correct
components, if not will hook up a double pole switch to +5 AND +12v for
each drive.
BTW I just got the 530 meg seagate ST3600N drive and hooked up to my
GVP 030 controller this drive gets speeds over twice as fast as my Quantem
105 lps, I was quite shocked at that much difference. Computer Shopper
has these drives for $318!
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
> I was quite shocked at that much difference.
It's amazing, isn't it? You are used to a certain speed and all of a sudden
it's REAL fast. Unofrtunately, it is too easy to get used to the new speed. 🙂
-larry
Very true words! My first hd was a 20 meg mfm seagate tied to a 2090
contoller, I thought I was in hog heaven!, when I upgraded to a 40 meg
quantem a year later, I thought it screamed, I was the envy of all my
friends! I have been using two quantem 105s for the last few years and
was quite content with their performance until now, they are dog slow!!!
Sysinfo shows the 105 at 998,010 bytes/sec, the new seagate is 2,037,388
bytes a second. cut my highly customized boot sequence from by over 30
seconds! Now I just have to get a SCSI II controller for the drive (what
is the saying about the difference in men and boys?!)
…Steve
Cruising on Autopilot
from beautiful Coastal South Carolina
I just spoke to someone that is STILL using a 60mb RLL drive with an Adaptec
4090…talk about slow..talk about scary..
Alex