greg@isrnix.UUCP (Gregory Travis) (02/17/88)
I have a number of questions regarding my hard disk. The disk is
a Xebec (9776 I think, I'm at work and the 'puter is home). Anyways, it's
a 20 meg drive which I believe is manufactured by NEC (I opened it up
once, just to peek). I bought it way back when hard drives for A1000's
were rare and it had the best published real transfer rates.
1) The drive is rated (according to the Xebec manual) at over 150K
bytes/second. Actual read transfer rate, going flat out, to my Amiga
seems to be around 25-30K, which stinks. I realize that the slow
seek time (85ms) may account for some of this. Will the
new hard disk filesystem help out at all? Will it even work with the
Xebec software?
2) I have noticed that when WRITING to the disk (say from Emacs
or a utility program) the activity light on the disk is
only on about 10-15% of the time spent writing - which indicates to me
that the software is not able to keep up with the turtle-powered
drive! What could be going on? I 'addbuffer' about 100 buffers for
the drive (which work out of my FAST memory! I experimented with
changing the BufMemType in the mounttable from 3 to 5 and it worked.
The Xebec manuals say nothing about this. Needless to say the gained
chip memory was welcome). However, the above behavior (sleepy writes)
happens with any number of buffers. This behavior (idle drive even
with outstanding I/O) also happens during reads, but then it is less
noticeable. Is the activity light a sign of seek activity? Could
the drive be writing to a single track over and over again (since the
interleave is 5:1 (yuck))? Even so, a full track write should take
less than 1/4 second! This is based upon a 2400 RPM rate and 10
revolutions to write the whole track (5 revolutions of interleave and
1 revolution each time just to account for any missed revolutions).
2) Is there any possibility that the drive will work with a
A2090 DMA controller? I may buy a 2000 some day and I would like to
keep the Xebec. It is a "modified SCSI" (whatever "modified" means).
3) Does anyone know what I have to send, and to whom (i.e. to SCSI.DEVICE
or DH0:), to park the drive? I would like to write a program which
sits in the background and parks the drive every 10 minutes or so.
4) Where can I get information on the controller itself? I would like to
know things like where in the address space the controller appears,
what the registers are and what bits do what (if this sounds wrong,
it's because I write PDP-11 UNIBUS drivers all the time and have never
written a 68000 driver).
Primarily, I am interested in improvements to the system software so that
any I/O related waits are due to waiting for the DRIVE to do
its work. I can't imagine why the drive would ever sit idle waiting for
the CPU to tell it what to do. Even if the filesystem is not optimized
for hard disks, shouldn't the disk be busy seeking all over the place?
System is an A1000, 2.5 megabytes of ram, 68010 processor.
Hi Karl!
I remain,
--
Gregory R. Travis
Institute for Social Research - Indiana University - Bloomington, IN 47405
ihnp4!inuxc!isrnix!greg
{pur-ee,kangaro,iuvax}!isrnix!greggreg@isrnix.UUCP (Gregory Travis) (02/24/88)
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
<> This is a reposting, the original didn't seem to make it out <>
<> of Bloomington! Apologies to anyone who's seen it already. <>
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
I have a number of questions regarding my hard disk. The disk is
a Xebec (9776 I think, I'm at work and the 'puter is home). Anyways, it's
a 20 meg drive which I believe is manufactured by NEC (I opened it up
once, just to peek). I bought it way back when hard drives for A1000's
were rare and it had the best published real transfer rates.
1) The drive is rated (according to the Xebec manual) at over 150K
bytes/second. Actual read transfer rate, going flat out, to my Amiga
seems to be around 25-30K, which stinks. I realize that the slow
seek time (85ms) may account for some of this. Will the
new hard disk filesystem help out at all? Will it even work with the
Xebec software?
2) I have noticed that when WRITING to the disk (say from Emacs
or a utility program) the activity light on the disk is
only on about 10-15% of the time spent writing - which indicates to me
that the software is not able to keep up with the turtle-powered
drive! What could be going on? I 'addbuffer' about 100 buffers for
the drive (which work out of my FAST memory! I experimented with
changing the BufMemType in the mounttable from 3 to 5 and it worked.
The Xebec manuals say nothing about this. Needless to say the gained
chip memory was welcome). However, the above behavior (sleepy writes)
happens with any number of buffers. This behavior (idle drive even
with outstanding I/O) also happens during reads, but then it is less
noticeable. Is the activity light a sign of seek activity? Could
the drive be writing to a single track over and over again (since the
interleave is 5:1 (yuck))? Even so, a full track write should take
less than 1/4 second! This is based upon a 2400 RPM rate and 10
revolutions to write the whole track (5 revolutions of interleave and
1 revolution each time just to account for any missed revolutions).
2) Is there any possibility that the drive will work with a
A2090 DMA controller? I may buy a 2000 some day and I would like to
keep the Xebec. It is a "modified SCSI" (whatever "modified" means).
3) Does anyone know what I have to send, and to whom (i.e. to SCSI.DEVICE
or DH0:), to park the drive? I would like to write a program which
sits in the background and parks the drive every 10 minutes or so.
4) Where can I get information on the controller itself? I would like to
know things like where in the address space the controller appears,
what the registers are and what bits do what (if this sounds wrong,
it's because I write PDP-11 UNIBUS drivers all the time and have never
written a 68000 driver).
Primarily, I am interested in improvements to the system software so that
any I/O related waits are due to waiting for the DRIVE to do
its work. I can't imagine why the drive would ever sit idle waiting for
the CPU to tell it what to do. Even if the filesystem is not optimized
for hard disks, shouldn't the disk be busy seeking all over the place?
System is an A1000, 2.5 megabytes of ram, 68010 processor.
Hi Karl!
I remain,
--
Gregory R. Travis
Institute for Social Research - Indiana University - Bloomington, IN 47405
ihnp4!inuxc!isrnix!greg
{pur-ee,kangaro,iuvax}!isrnix!gregcmcmanis%pepper@Sun.COM (Chuck McManis) (02/24/88)
In article <883@isrnix.UUCP> greg@isrnix.UUCP (Gregory Travis) writes: ><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> ><> This is a reposting, the original didn't seem to make it out <> ><> of Bloomington! Apologies to anyone who's seen it already. <> ><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> It did, just no one commented on it. Or maybe none of the comments made it back to bloomington. > 1) The drive is rated (according to the Xebec manual) at over 150K > bytes/second. Actual read transfer rate, going flat out, to my Amiga > seems to be around 25-30K, which stinks. Welcome to the world of the AmigaDOS filesystem! Yes it stinks, yes it is fixed by the Fast File system, no you can't get the Fast File system until 1.3 comes out and I have no idea of when that would be. > 2) I have noticed that when WRITING to the disk (say from Emacs See above. Writing is still less than optimal. > 2) Is there any possibility that the drive will work with a > A2090 DMA controller? I may buy a 2000 some day and I would like to > keep the Xebec. It is a "modified SCSI" (whatever "modified" means). Should if it talks *real* scsi, whatever that is. My guess would be that it will. Although it won't be any faster until the FFS arrives. > 3) Does anyone know what I have to send, and to whom (i.e. to SCSI.DEVICE > or DH0:), to park the drive? I would like to write a program which > sits in the background and parks the drive every 10 minutes or so. Only the Authors of the Driver for your particular disk know that, call Xebec. Sorry I can be more help here. > 4) Where can I get information on the controller itself? I would like to > know things like where in the address space the controller appears, > what the registers are and what bits do what (if this sounds wrong, > it's because I write PDP-11 UNIBUS drivers all the time and have never > written a 68000 driver). First read the expansion spec for the Amiga, primarily because where exactly the hardware appears will vary somewhat. Then get a technical manual from Xebec. Xebec is not on the net that I know of, maybe someone who has one and has gone through a similar process will respond. >Primarily, I am interested in improvements to the system software so that >any I/O related waits are due to waiting for the DRIVE to do >its work. I can't imagine why the drive would ever sit idle waiting for >the CPU to tell it what to do. Even if the filesystem is not optimized >for hard disks, shouldn't the disk be busy seeking all over the place? Why not get some of the public domain stuff like Matt's Packet Monitor and track down where you are spending your time. I think you will need to learn a lot more about the Amiga OS's internals which is not impossible but is beyond the scope of this article. Some pointers to help you along the way --> BOTH volumes of the Rom Kernel Manual, Read them cover to cover including the include files, three times. --> Rob Peck's book which has a decent overview of how the Amiga's OS is layered. --> The Kickstart Guide to the Amiga which has some more obscure Exec type information in it. ---> All of the include files/ Readmes/ Autodocs on the Native Developers Update disk ($20 from CATS, 1200 Wilson Dr, West Chester, PA, 19380) --> All I/O code that appears on any Fish disk, this includes Matt's device and handler routines, the Pipe: handlers, the simple SCSI hard disk driver and the example device from the RKMs If you have any specific questions after that please let us know :-) Seriously, the information is all available, it just isn't coalesed(sp?) real well. --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.
andy@cbmvax.UUCP (Andy Finkel) (02/26/88)
In article <883@isrnix.UUCP> greg@isrnix.UUCP (Gregory Travis) writes: > 1) The drive is rated (according to the Xebec manual) at over 150K > bytes/second. Actual read transfer rate, going flat out, to my Amiga > seems to be around 25-30K, which stinks. I realize that the slow The FastFileSystem should help, yes. Assuming your Xebec software is a device that lets you use the Mount command to mount the filesystem, it should work. (I don't have the Xebec, so it is a bit of speculation; but it should work...) > 2) I have noticed that when WRITING to the disk (say from Emacs > or a utility program) the activity light on the disk is > only on about 10-15% of the time spent writing - which indicates to me > that the software is not able to keep up with the turtle-powered > drive! What could be going on? I 'addbuffer' about 100 buffers for Adding buffers is not expecially effective under the standard file system. FFS does much better, adding buffers makes a big difference. > 2) Is there any possibility that the drive will work with a > A2090 DMA controller? I may buy a 2000 some day and I would like to > keep the Xebec. It is a "modified SCSI" (whatever "modified" means). I've talked to 2 people who tried...neither with much success, though. We don't know how they modified SCSI, though. -- andy finkel {ihnp4|seismo|allegra}!cbmvax!andy Commodore-Amiga, Inc. "Never test for an error condition you don't know how to handle." Any expressed opinions are mine; but feel free to share. I disclaim all responsibilities, all shapes, all sizes, all colors.
alexr@xicom.UUCP (Alex Laney) (03/14/88)
[ line eater space here for backwards compatibility ] I would like to know how to fill out a mountlist for a SCSI streaming cartridge tape drive attached to the A2090. Anybody out there done this yet? Will I have to "format" it? If there is a manual with this info? It is a QIC-24 tape drive. [ By the time I get any replies, I probably will have tried it, anyway, but I don't hold out much chance for success. ] Thanks in advance,
GIGUERE@WATCSG.BITNET (Eric Giguere) (02/17/89)
No doubt this question has been hashed and rehashed on the net, but
here goes: I'm seriously considering buying a hard drive for my 2000.
Purely for the Amiga side. I intend to purchase the Commodore
controller. Now the big question: should I go SCSI or ST-506? I've
had conflicting opinions on this one. I can purchase the same setup
that's found in the 2000HD for about CA$1000, which is reasonable for
my budget -- it's a 28 ms ST-506 drive, 40 megs. Is it true that a
SCSI drive with FFS installed is much faster? What is the exact
difference between SCSI and ST-506 anyhow?
I'd appreciate any answers.... either to the list or to me directly.
Thanks.
Eric Giguere
Computer Systems Group, University of Waterloo
GIGUERE@WATCSG.BITNET or GIGUERE@UNCAMULT.BITNET
P.S.: On a totally unrelated matter, I'm looking for an interesting
use for Yacc/Bison on the Amiga. I'm writing a 2-part article
for the Transactor for the Amiga on using Bison and I'm looking
for a better idea than the standard "calculator" grammar. If
you have an idea (the grammar has to be fairly short), please
mail it to me. Thanks.fleabag@athena.mit.edu (Jeff Bellsey) (04/13/89)
to start off with, i am IGNORANT. i am not even an amiga owner (still in the looking stages). i'm looking at hard drives and seeing many wonderful deals, but i don't know if they're useful. sooo... what controller format does the amiga use? st506? scsi? both? which is faster/more reliable? is there something else i need to know? thanks in advance... :bags fleabag@athena.mit.edu