Adaptec AHA-2940U2W problems when burning on the fly! Guyver?

[Chucky Cheese]

Jake

are you terminating that bus with an "lvd" terminator or do you have that cheetah forced in se mode?? is the hd on the same bus as the removable media?? i have 4 of those drives at the moment and was thinking about going to a raid 0 or 5

it has been my observation that if you don't use a terminator that is made for "lvd" the the scsi bus is unreliable and could cause system instability. i am running win2k only but i do use cdrwin3 and nero.

SYSTEM;

Motherboard: AMI MegaRUM II, dual 600Mhz Pentium III processors (installed), each with a 32/512 Cache configuration. 512 Mb of PC100(CAS3), 8ns memory. Symbios Logic 53C896 U2W SCSI controllers. Intel 443GX Xeon chipset.

SCSI I/O:

Channel 1(LVD/U2): 4 Seagate LVD Cheetah 18LP, ST39103LW Ultra2 Wide SCSI-3 hard Drives, each with 1024k cache.

Channel 2(SE): JAZ 2GB internal, Plex-Writer 8/20, Pioneer DVD-303s ultra-scsi DVD reader and 2 UltraPlex-Wide 17/40 speed CD-ROM drives.

USB: USB Zip Drive, Epson Stylus Scan 2500, Intellimouse Explorer

Networking: The network adapter is a 3Com 3C509B-TX PCI 10/100 Mbps controller, and a US Robotics Courier V.Everything 33.6/28.8/x2/V.90 internal ISA modem.

Video: Matrox G400 Max with Dual Head. The primary display is a Panasonic PanaSync E21, .25-dot pitch, 20" viewable; the secondary display is a Samsung 17" Flat Panel Display(.264mm pitch) model 770TFT.

Multi-media: Creative Labs Sound Blaster Live PCI Bus Mastering sound card. Speaker system is the Cambridge Works FPS2000 Digital speaker system.

i'll be snapping in a couple 800 mhz pIIIs' in a couple of weeks!!!

chucky

[Jake]

Brain fart! LOL! I love that expression!

That's one impressive rig you got there Chucky!

Four 9.1GB Cheetahs?? BAD MOFO! is that two seperate PCI U2W SCSI controllers or one dual-channel? Why two CD-ROM drives and a DVD-drive?

With 4 SCSI HDD's I should think your rig would rock in RAID 0 or 5! Only problem is I don't know exactly how great it works. Have never tried it. I only have one 9.1GB Cheetah 18LP, but I'm considering gettting one more and setting them up in RAID 0 for the I/O performance gain. (Double throughput). The Cheetah 18lp measures 26 MB/s sustained throughput in my system, which means that no more than 3 HDD's should be used in RAID 0 configuration, because the total throughput should never exceed the 80Mb/s bandwidth of the Lvd bus.

To answer your questions: When you say "on the same bus", you mean on the same channel, right? The Lvd HDD is connected to the lvd/SE connector and has an active termination block installed on the cable. How do I make sure it's not running in SE mode? The CDR and CD-ROM use the 50 pin 8-bit SCSI connector (Regular Ultra-SCSI not wide). As you know the Aha-2940U2W is a single channel controller. Should this affect the performance or stablilty?

I should think that the optimal config for you in W2k would be to use one Hdd as boot-drive and the other three in a Raid 0 or 5 setup. The perfect sollution would be to get a hardware RAID controller, but I should think that considering your powerhouse rig, that it would cost you little in terms of system overhead on your Dual processor system just to use software RAID. Especially if your PC is not set up as a server, but as a stand-alone workstation.

I'm going to do a little more research into the performance of W2k software RAID, but it sure sound like a great sollution.

Regards,

Jake


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Who is General Failiure and why is he reading my drive?
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MGA-G400DH 32Mb Mill., Abit BF6 mobo bios ver. QJ, PIII-450@558, 128Mb PC-133 SDRAM, 17" Hitachi monitor, Plextor 40TS CDROM, Plextor 8/20 CDR. Diamond MX300 A3D PCI soundcard, Adaptec AHA-2940U2W, Seagate Cheetah 9.1 GB LVD HDD, Quantum Fireball ST 6.4 GB UDMA33 HDD



[This message has been edited by Jake (edited 05 May 2000).]

[Chucky Cheese]

Jake,

if i'm reading your description of your scsi controller right you have a single channel, dual-connector controller right?? if so your hdd is running in se mode(..ie 8 bit). you should see two distinct channel setups when accessing the scsi bios. the moment you connected the narrow devices you limited the bus to 8-bit, see if you can aquire a dual channel card, the only drawback is that it will require 2 irqs'. there is a jumper on the bottom of the drive to force it into se mode.

my scsi controller is built-in and is a single chip, dual channel solution. i bought my terminators(..68 pin) from granite digital(..$100 each) and they have lights on them to show what mode the scsi bus is operating in.

i do have the raid card for this mobo with 64 mb of 72 pin edo memory on it. as far as multiple drives...no particular reason really...i don't use my recorder for installing software, likewise i don't use the dvd player for anything other than dvd/mpeg stuff..i'm just square that way.

chucky

[Jake]

Chucky,

Is this something you know for a fact or are you guessing? I mean the controller IS single channel, and actually has 3 connectors, 1 Ultra-SCSI 50-pin, 1 Wide-SCSI 68-pin, and 1 SCSI-LVD connector 68-pin.
The adaptec EZ-SCSI software tells me my HDD runs in 16 bit mode! Can't the channel communicate in 8 and 16 bit mode at the same time?

Damnit! This controller wasn't cheap. It should be able to communicate in LVD mode even if narrow devices are connected to the 50-pin connector. It just makes no sense to build a "multiple connector" card if using different devices forces it into the slowest mode. Then I might as well have bought an old narrow 8-bit HDD!

I'll have to check my documentation again and maybe Adaptec's web-site.

Thanks,

Jake

[MultimediaMan]

The Adaptec 2940U2W is a two channel adapter.

The external and one of the internal 68 pin connectors comprise channel#1. The other 68 pin OR the 50 pin internal comprise channel #2. Channel #2 can be a 16 bit OR an 8 bit host without using a cable adapter (The 50 pin connection on the card incorporates a high byte terminator to allow the use of 8 bit devices.) , but that doesn't mean that you won't need a cable adapter...more on this later.

Whenever you run an 8 bit (50 pin) device on a 16 bit (68pin) channel of a SCSI adapter, the entire channel is dumbed down to 8 bit. So what about mixing 16 bit and 8 bit devices?

If you use a 16 bit device (68 pin) on channel #2 in conjunction with an 8 bit device (50 pin), you CANNOT use the 50 pin connector on the 2940U2W. You must use a 68 to 50 pin adapter on the 68 pin ribbon cable.
Adaptec has a nice diagram with several common setups here:
http://www.adaptec.com/support/confi...n/connect.html

After looking at the how Ultra SCSI and Ultra Wide devices interact on the same channel, it becomes very clear why a multi-channel setup is desirable for CD burning. I use three channels to get a bit more flexibility - an O/S Drive channel, CD Cache File/CD Source Drive channel, and the CD-Burner channel (or will rather once I get that Plextor UltraplexWide). SCSI is still damn fast, and any ultra wide source is overkill for feeding a CD-R an uninterrupted stream of data - but the security is nice.

Buffer underruns can still result from too many devices on the same SCSI channel, (like older IDE CD-ROMs and CD-Burners sharing the same channel doing a CD to CD transfer). Remember too that the SCSI ID on a given channel also determines the priority of the device.

[Chucky Cheese]

Jake,

while i haven't used adaptec hardware for awhile and i'm not familiar with that controller in particular,, i am sure about that(..8/16 bit negotiation). i helped a friend of mine through the same problem with a 2940u controller...he was upset also. i would get terminator like mine and know for sure, i know their pricey but worth it.

i'm having no problems with the removable media on one channel and fixed disk on the other. my #2 channel is terminated ouside the case and the hdd channel is not.

i don't know if this will help but standard scsi protocol says to diable sync negotiation and set the device to its' highest rated transfer rate...and make sure your windows settings match what you setup in the controller bios for each device...i have found this to be a good guideline for removable media but not for hdds, hence the mixing and matching of different speed/protocol device is generally not recommended

chucky

[xortam]

Software RAID (vs. hardware) will not only yield less performance but it also limits the hosting of multiple OSs (unlike hw versions).

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• ASUS P2B-S, PIII 450MHz, Award ACPI BIOS v1010, 128 MB RAM
• MYLEX FlashPoint RAID+ (BIOS v2.02N) running RAID 0 on two 9 GB IBM DDRS 39130D Disks
• Diamond MX300 sound card, now with MX25 S/PDIF output
• Matrox Millennium G400 Max Dual Head - English
• NEC 5FG monitor
• Logitech MouseMan Wheel
• YAMAHA CRW4416S and NEC Multispin 3x CDs
• 3Com Fast EtherLink XL 10/100Mb TX NIC (3C905B-TX)
• US Robotics 56K Voice FaxModem Pro
• Pioneer DVD-303S SCSI
• Note--All SCSI devices (except disk drives on RAID) are connected to onboard AIC7890 U2W SCSI
• Mainly running Win98 v4.10.1998

[Jake]

I just checked the documentation that came with my AHA-2940U2W. It seems the LVD segment seperated from the Ultra/Fast Segment. So my LVD HDD should run in 16 bit mode. Sandra says so too.



Pheeew!

Xortam, have you tried software RAID 0 spanning two drives or more in W2k or NT4? How does it perform in comparison to Hardware RAID? Benchmarks?

Regards,

Jake

[This message has been edited by Jake (edited 06 May 2000).]

[MultimediaMan]

Uh, just like I said in my earlier post...

[Jake]

Multimediaman,

I still claim that the 2940U2W is a SINGLE-channel controller. It's just able to keep the two segments isolated using the SpeedFlex technologi. If it was two-channel attaching CD-drives to the UltraSCSI connector would not affect bandwidth on the LVD segment. On this controller it does. I'm still limited to 80/Mb pr. second total throughput at the same time on the controller. Otherwise you were right.

Just had to make sure as I was getting conflicting info here.

Anyway, a thank you to you all.

Regards,

Jake

[MultimediaMan]

Jake,

[MultimediaMan]

Jake,

I see now the difference in terminology...not the SCSI segments but the actual BUS bandwidth capability of the card. In order for the 2940U2W to be TRULY dual channel would be to use a PCI to PCI Bridge and a controller for each side of the bridge, as the 39XX series does.

Sorry for the confusion.

Best,

MultimediaMan

[Chucky Cheese]

Jake,

just for my own info...are there two distinct channel setups in the controller bios?? i've owned(..not now) a couple of versions/flavors of the 2940 and 3940s and beta tested ez-scsi 5.0...i just found that the symbios/lsi controllers were slightly faster.

it has been my personal experience that the most the scsi periphials can achieve is about half of the interface rating, then you start factoring in controller overhead, number and type of devices, os overhead and other factors. i don't benchmark, but the last time i did, these drives in this setup averaged between 27-34 MB/sec(..scisandra 99). as long as things are snappy..i'm happy.

chucky

[Jake]

Hi Chucky.

All I can say is that in the SCSI bios setup, no destinction is made between channels. That, by the way also led me to conclude for certain, that my 2940u2w IS single channel. When setting options for the individual SCSI ID's all there is in the bios is 16 different rows, one for each possible peripheral on the SCSi chain. No destinction is made between "channels". Why should there be if there is only one?

Oh, I almost forgot. GUYVER! You asked for advice on what SCSI CDRW to buy way back on this thread. Well, on of my homies bought the Plextor PX-W124TS 12/4/32 CDRW about two months ago. That's a BAD mutha! Burns at 12X! I don't think he has made a single coaster yet! SUPER!

Regards,

Jake


[This message has been edited by Jake (edited 06 May 2000).]

[xortam]

Jake, I haven't personally tried software RAID but I did see some benchmarks comparing HW RAID and NT4 SW RAID that showed the performance differences. I don't recall where I saw this but it was probably a HW vendor web site ... perhaps Adaptec. I was looking into this a year ago so there wasn't any W2K benchmarks at the time. I think you're just asking for trouble using SW RAID: How do you fix a system that won't boot up the OS?

As has been previously stated ... the 2940U2W (and similarly the on-board AIC7890) utilize a single channel but use the Adaptec SpeedFlex technology to isolate the U2W devices so at to not impart any performance degradation (very nice economical feature). Though it is a single channel controller, there are two busses that each need to be terminated (total of four termination points).

As far as mixing in IDE devices with SCSI ... I considered an IDE DVD but I didn't want to give up another interrupt (and I like the flexibility of SCSI, e.g. external box, keeping it cool!!!).