Subject: RE: Hard drives on a IIci
To: jshenry <>
From: Tod McQuillin <>
List: port-mac68k
Date: 10/27/2000 10:23:44
On Fri, 27 Oct 2000, jshenry wrote:

> Those Seagates do draw a lot of current. I have some Hawk series drives that 
> won't startup in several of my enclosures because they draw too much starting 
> current.

On the other hand, I have hawk ST12400N's in my IIcx and IIci and they
spin up fine.  So if you have a hawk it's at least worth a try.

According to the manual the power supply is supposed to shut down if too
much current is drawn from it.  I have confirmed this by accidentally
shorting the power supply a couple of times[1] :-)  Maybe that feature
doesn't always work right at the boundary conditions.

> The green light just stays on solid, but the spindle motor never
> starts.

That can also be a symptom of having the ME (motor enable) jumper
installed.  This jumper is counterintuitively named, because installing it
means the motor does *not* start until it receives a 'Start Unit' scsi
command (which the Mac II series does not appear to send).  When the ME
jumper is not installed, the motor spins up immediately after power on.

(This is from the my Hawk manual, but many other seagate drives use the
same convention.)

> Apparently, the power supplies in the PowerPC machines are a bit heftier, 
> though. I have a 2Gb Hawk mounted in the drive bay of a 7100 (running 
> mkLinux), and it starts just fine.

Or maybe the open firmware on the PPC sends a start unit command where the
m68k mac roms didn't.

> I would suggest an actual hard disk enclosure.

This could be a good idea anyway, since the ventilation in the case might
not be sufficient for some hot running drives.
Tod McQuillin

[1] by accidentally plugging an external monitor into an AUI ethernet
port.  Oops... now the aui ports have tape over them.