Universal SGI disk solution: 15kRPM 300GB SCA SCSI drives

Elf

Storybook
Feb 4, 2019
478
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Common wisdom (based on lots of discussions in chat) is that a more or less universal solution to storage on the SGI MIPS machines is the use of cheap and available 15kRPM 300GB 80 pin SCA connector SCSI drives, with an 80 pin SCA to 50/68-pin adapter if necessary.

Specifically I am using the Seagate ST3300655LC (which can be found cheaply on eBay brand new) and:
  • For 50 pin conversion: a common unbranded mystery SCA 80 to 50/68-pin adapter
  • For 68 pin conversion: a common unbranded mystery SCA 80 to 68-pin adapter
Note: After some time, the eBay links that were above are no longer valid. Since I haven't purchased any more of these, I can't vouch for any versions from other eBay sellers, but you can search for similar ones on your own. I have posted photos of mine below to assist.

As I go through my systems and replace the drives with this solution, I will mark off compatibility. If you have a system (whether or not it is in the table below) and you have had success or failure with this combination, please post and I will add it to the list! Please note which SCSI bus / adapter the drive was on, if applicable.

SystemSCSI adapterWithout 80 to 50/68 adapter boardWith 80 to 50/68 adapter board
Challenge LN/A☑ Successful (unknown adapter)
Indigo 1
Indigo 2MotherboardN/A☑ Successful (50/68 pin combo)
IndyMotherboardN/A☑ Successful (50/68 pin combo)
O2Motherboard☑ SuccessfulN/A
OctaneMotherboard☑ Successful
FuelMotherboardN/A☑ Successful (68 pin non-combo, see Note 1)
TezroIO9☑ SuccessfulN/A
Note 1 (Fuel 80 to 50/68 pin adapter): I have not had success with the Fuel and the 50/68 pin combo adapter personally. The drive does not spin up if the SCSI cable to the host is connected, but will spin up if it is not connected; I have also found similar older posts by others. However, others (e.g. LarBob) have reported success, and I also had success after ordering the 68 pin non-combo adapter. It may be that not all adapters are created equal?
 
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LarBob

Administrator
Feb 8, 2019
42
16
8
Probably worth noting that I have had success on the Fuel with that drive and a 68pin adapter board. There seems to be some variance within those adapters somehow.
 

massiverobot

irix detailer
Feb 8, 2019
102
74
28
Philly
twitter.com
I have used them, without any issues in :

1. My O2 (two of them)
2. My Octane
3. My Challenge L
4. My I2i Max
5. My Fuel

They have used various cheap adapters to get the SCA where it needs (SCSI SE 50 pin, 72 pin) to be (except for O2 and Octane).

The Drives I used were called like "HP 412751-016 300GB 15K U320 HDD *New Bulk*" I see there are some compaq branded ones. They all work very well and are very quiet.
 

Elf

Storybook
Feb 4, 2019
478
129
43
I have used them, without any issues in : [...]
Good info!

Do you know what adapters you used in the Challenge L and Indigo 2 Impact? Also I remember you had to take care with the Challenge using the SCSI SE interface to avoid burning it out on the HVD interface. What SCSI adapter was that; motherboard or expansion card?

It might be good to post some info about connecting it to the correct interface to save others some pain!
 

Unxmaal

Administrator
Feb 8, 2019
96
57
18
I second this. I've bought several of these drives from various eBay vendors. At this point it's the only type of drive to buy for SGI gear.
 

Elf

Storybook
Feb 4, 2019
478
129
43
I2I SCA adapter.jpg

Just wanted to report in my own success with an Indigo 2 (Impact), the 300GB 15kRPM SCA drive, and the 50/68 pin adapter.

Funny, as the trays have an SCA-like presentation to the backplane, but present a 50 pin cable on the drive sled. I am unsure if the backplane connection is actually SCA or whether they just used that connector. It requires being jammed in a bit to fit the 50/68 pin adapter between the drive and the drive sled, but it all works in the end as long as you make sure the cables do not poke out too high.
 

callahan

Member
Jul 20, 2019
37
24
8
Supposedly they are SCA adapters, but in the wrong location so you can't directly connect a drive.
 
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drmadison

New member
Jun 30, 2020
27
11
3
Does anyone else notice these running a lot hotter than slower drives?
I replaced the spinning drives in both of my O2s with some 15k rpm fujitsu and after powering down I pulled a drive from one and it was almost to the point of being too hot to touch. Possible it's just that specific drive but curious of others have had similar experiences with temps on these?

I think I'd rather go smaller / slower but cooler given that the O2 can't push it to its limit to begin with?
 

weblacky

Member
Jan 13, 2020
91
23
8
Seattle, WA
Yeah, I don't know WHY people keep recommending 10K and above drives for SGIs stations, likely because they're now cheap from old NAS/RAID units. I know some are cheap now, but only SCSI drives UNDER 10K don't need active cooling. So the 36K drives people get and everything...require active cooling...they've always said that in the drive manuals!

Get a nice 7200 RPM drive. Most drives UNDER 20GB are drives that need less cooling because they were for stations and PCs. Drives getting into 30GB+ tended to be faster for RAID units. Irix doesn't need much space, so I tell people to stick to between 6GB to 19GB drives. Though some drives (like fujitsu, (before Seagate) Quantums, and Samsung (before seagate) run nice and cool and are great for work stations. Also I run a lot of IBM SCSI drives in my O2s. They run fine, deathstars were later and IDE. SCSI Hitachi and IBM station 1" low-profile drives using SCA work great in O2 models.

So I highly recommend tracking down IBM and Hitachi SCA SCSI drives in lower densities for O2 stations, and SCA Fujitsu and other higher-end brands before they got bought up by Seagate.
 

weblacky

Member
Jan 13, 2020
91
23
8
Seattle, WA

Just wanted to report in my own success with an Indigo 2 (Impact), the 300GB 15kRPM SCA drive, and the 50/68 pin adapter.

Funny, as the trays have an SCA-like presentation to the backplane, but present a 50 pin cable on the drive sled. I am unsure if the backplane connection is actually SCA or whether they just used that connector. It requires being jammed in a bit to fit the 50/68 pin adapter between the drive and the drive sled, but it all works in the end as long as you make sure the cables do not poke out too high.
Make sure you place a piece of cardboard between the rear of the drive and the green PCB SCA adapter board (sitting on the SCAN connection). I've had several where the compression was so high, the board connector leans forward, nearly touching the rear casing of the drive (PCB solder joints to metal casing!). So I placed a cardboard (gum stick sized) buffer so that shorts couldn't occur.
 

Jacques

Member
Dec 21, 2019
72
31
18
Somerset, United Kingdom
drmadison - I had an HP branded Fujitsu 72gig drive do exactly that, almost scalding hot to the touch in my Octane. A couple of weeks later it made the bearing whine of death sound and wouldn't spin up again, this was only 3 weeks after I got the system and after doing a fresh IRIX install. The bearing had completely seized. I have two Seagate 146gig drives, one has started to develop a whine so it stays very far away from any system. The other Seagate is just very, very loud!
 

indigofan

Member
Jun 8, 2020
34
14
8
Common wisdom (based on lots of discussions in chat) is that a more or less universal solution to storage on the SGI MIPS machines is the use of cheap and available 15kRPM 300GB 80 pin SCA connector SCSI drives, with an 80 pin SCA to 50/68-pin adapter if necessary.

Specifically I am using the Seagate ST3300655LC (which can be found cheaply on eBay brand new) and:
As I go through my systems and replace the drives with this solution, I will mark off compatibility. If you have a system (whether or not it is in the table below) and you have had success or failure with this combination, please post and I will add it to the list! Please note which SCSI bus / adapter the drive was on, if applicable.

SystemSCSI adapterWithout 80 to 50/68 adapter boardWith 80 to 50/68 adapter board
Challenge LN/A☑ Successful (unknown adapter)
Indigo 1
Indigo 2MotherboardN/A☑ Successful (50/68 pin combo)
IndyMotherboardN/A☑ Successful (50/68 pin combo)
O2Motherboard☑ SuccessfulN/A
OctaneMotherboard☑ Successful
FuelMotherboardN/A☑ Successful (68 pin non-combo, see Note 1)
TezroIO9☑ SuccessfulN/A
Note 1 (Fuel 80 to 50/68 pin adapter): I have not had success with the Fuel and the 50/68 pin combo adapter personally. The drive does not spin up if the SCSI cable to the host is connected, but will spin up if it is not connected; I have also found similar older posts by others. However, others (e.g. LarBob) have reported success, and I also had success after ordering the 68 pin non-combo adapter. It may be that not all adapters are created equal?
I've ordered the 50/68 adaptor for my Fuel and will update if I have success or not with it.
 
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indigofan

Member
Jun 8, 2020
34
14
8
I finally got the adaptor, took forever to arrive from China. Got nothing but SCSI errors with the 80 to 50/68 adapter board on a Fuel. Tried many jumper combinations on the board and nada, does not work. So, could of been the item that I received (still going to try it on an older PC) or an SGI compatibility issue.
 

Elf

Storybook
Feb 4, 2019
478
129
43
I also had trouble with the Fuel and 50/68 adapter; perhaps try one of the 68 pin only adapters? That was what ended up working for me.
 

weblacky

Member
Jan 13, 2020
91
23
8
Seattle, WA
Most likely you are running into the issue from forcing Single-Ended (SE) mode on a Low Voltage Differential (LVD) bus.

The SCSI architecture for the Fuel should be running at least Ultra160 LVD (if not more). These are Low Voltage Differential signalling buses. Now for many SCSI adapters (that also have interactive firmware, like Adaptec). You could FORCE an LVD bus back into the Parallel SE mode. This is what 50-pin (Narrow) and 68-pin (Wide/Ultra-Wide) are. You CANNOT mix the two, a SCSI chain runs at the slowest bus standard of all devices present on it. So if you put an LVD device and an SE device on the same chain...they both need to run as SE (good luck with that in practice).

However (regardless of SGI), I've seen embedded SCSI controllers for servers that were LVD-only and absolutely threw a fit when you tried ANY SE devices. They hated it, refused to do it, and generally were considered LVD only. I assume the last SGIs were configured this way.

The adapter you got IS SE. Because it has 50 pin, this isn't an issue with active termination of the 68->50 pins...you're attempting to downgrade the actual SCSI signaling standard to an obsolete one (in terms of the Fuel's perspective).

You need to be use something like this: https://cs-electronics.com/product/adp-9018-sca80-68-lvdse-for-ultra23-and-ultra160320-1-form-factor/

Please note the need for this kind of thing is RARE, the need to change a SCA drive to Ultra160/320 68 pin connector was just was never an expected thing. So I understand your issues, but while SCA drives are cheap, that's not what the Fuel takes (which is odd, considering the other SGIs DO take them). So be extremely careful not to mix SCSI standards. You won't blow up anything, but you're forcing the controller to a whole other signalling protocol...and even thought it should work, I'm not surprised it's throwing a fit. Many Ultra SCSI controllers were not really tested for SE and many either have intermittent problems or just outright refuse to work on an old SE device.

My advise, either buy a normal Ultra160 HDD (or get the right adapter, if you can) and then put in a AHA-2940UW card in the FUEL to run external and internal SE devices off that card. (since that's the correct standard for that adaptec card).

I've seen entire SCSI LVD array enclosures that worked ONLY on LVD and any SE devices caused firmware crashes. It's a thing.
 
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3ddoc

New member
Jan 17, 2020
23
14
3
Does anyone else notice these running a lot hotter than slower drives?
I replaced the spinning drives in both of my O2s with some 15k rpm fujitsu and after powering down I pulled a drive from one and it was almost to the point of being too hot to touch. Possible it's just that specific drive but curious of others have had similar experiences with temps on these?

I think I'd rather go smaller / slower but cooler given that the O2 can't push it to its limit to begin with?
good choice, heat kills
 

jenna64bit

Member
Apr 18, 2020
35
10
8
On that note, what’s a good low-temp drive for an O2? I’m having a bit of trouble finding a 7200rpm drive that’s 36GB+ for mine. Thus, I’m using one of the 15K drives Ian recommends that I’d rather put in my Octane2. I’m assuming with the SCA setup, one of those acard IDE adaptors is out of the question? I don’t know much about those but would assume their speed is ‘OK’.
 

fraserN64

New member
Aug 20, 2019
18
9
3
sites.google.com
@Elf could you update the adapters mentioned? It's been a year and a half and they are no longer listed so no pictures aren't available to use to find another similar adapter.
Thanks!
 

Elf

Storybook
Feb 4, 2019
478
129
43
I had to hunt around a bit to find extras, but here are some photos of the adapters I use. I removed the eBay links above. You can find boards very visually similar to the ones below, and please report in if you have any success with them, but I did not want to endorse any particular vendor since the suitability of the individual boards seems to vary and I have not bought any recently.

SCA to 50/68 pin
SCA-50-68-1.jpg

SCA-50-68-2.jpg


SCA to 68 pin only
SCA-68-1.jpg

SCA-68-2.jpg
 

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