This is part of The Pile, a partial archive of some open source mailing lists and newsgroups.
Subject: Re: problems when mounting my scsi cdrom From: Sam <sam@asatek.com> Date: Thu, 03 Jun 1999 19:12:26 -0400 Dawid Michalczyk wrote: > Detected scsi CD-ROM sr0 at scsi0, channel 0, id 3, lun 0 > sr0: disc change detected. > and here is how my cdrom2 fstab entry looks: > /dev/sr0 /mnt/cdrom2 iso9660 noauto,ro,user 0 0 > when I try to mount cdrom2 I get "special device dev/sr0 does not exist" > > what should I do to mount my scsi cdrom? Easy one once you know. I had the same problem, but no one answered. I found it in the docs. Use sdc0 as below at the command prompt or change sr0 to sdc0 in your /etc/fstab: mount -t iso9660 -r /dev/sdc0 /mnt/cdrom It worked great! === Subject: RE: problems when mounting my scsi cdrom From: Uncle Meat <kcsmart@worldinter.net> Date: Thu, 03 Jun 1999 19:17:11 -0500 (CDT) On 03-Jun-99 Dawid Michalczyk opined: > SCSI cd detection problems > > Just installed RH6 and have problems when mounting my scsi cdrom. > Here is what dmesg says: > > scsi : 1 host. > Vendor: TEAC Model: CD-R55S Rev: 1.0G > Type: CD-ROM ANSI SCSI revision: 02 > Detected scsi CD-ROM sr0 at scsi0, channel 0, id 3, lun 0 > sr0: disc change detected. > > and here is how my cdrom2 fstab entry looks: > > /dev/sr0 /mnt/cdrom2 iso9660 noauto,ro,user 0 0 > > when I try to mount cdrom2 I get "special device dev/sr0 does not > exist" Mine used to say the same during boot. But, the drive was on /dev/scd0 instead. I'd try that. === Subject: problems when mounting my scsi cdrom From: Kayvan Aghaiepour Sylvan <kayvan@sylvan.com> Date: Thu, 3 Jun 1999 18:21:40 -0700 (PDT) You can do this: mknod /dev/sr0 b 11 0 That should do it. ---Kayvan === Subject: Re: cmd to reinitialize SCSI bus ? From: "Jose M. Sanchez" <opjose@ex-pressnet.com> Date: Mon, 21 Jun 1999 17:17:34 -0400 heather casler <heather=casler%eng%emchop1@fishbowl02.lss.emc.com> wrote: > I know it's not a good idea to pull the cable when you're > doing I/O, but I'm doing a test and part of it is to see > how the host will react to a cable pull and to determine > what needs to be done to get the host back up and running > with the least amount of down time. For instance, what > would the Linux host do if someone tripped over the SCSI > cable? I was looking for a command that could be used to > go out and search the bus without having to reboot or > power down the system. Something like drvconfig in > Solaris or vgscan in HP or scsiha in SGI....anything in > Linux that will allow me to recover/renegotiate the SCSI > connection without having to reboot? The problem is that these devices are not designed to survive that type of event. There is no optical isolation of the lines, so often the scsi controller itself will freeze or at best lose communication with all devices on the SCSI chain... Linux has no mechanism for directly dealing with a hung adapter, though it does a pretty good job of automatically re-initing hung scsi devices if it fails to get a response within a predetermined amount of time... Suffice it to say, that if someone trips over the scsi cable, the system will need to be rebooted... after it has been powered off and all the connections re-established... You could potentially attempt to unload the SCSI drivers from the kernel, if the system is not frozen, but you'll find the kernel will recognize that the device is still mounted and prevent this. You'll also be unable to dismount the device, since Linux will be unable to flush it's buffers... (hmm if you get this far then maybe the SCSITOOLS might help you...) Round and round it goes... === Subject: Re: cmd to reinitialize SCSI bus ? From: "Jose M. Sanchez" <opjose@ex-pressnet.com> Date: Fri, 18 Jun 1999 17:37:28 -0400 Not a very good idea! At this point linux (and any OS for that matter) will be unable to dismount filesystems and write out any changes... Try typing sync;sync;sync;halt Then shut the system off... Plug that cable back in (THIS TIME WITH THE POWER OFF!) And let linux fsck the drives, keep your fingers crossed, bow to the east and west, and say "there's no OS like Linux" three times in a row... -JMS === Subject: Re: Problem Accessing SCSI Disk From: Jan Carlson <janc@iname.com> Date: Sun, 20 Jun 1999 00:02:39 -0400 Donnie Barnes wrote: > > On 19 Jun 1999 20:09:33 -0400, Trevor Astrope <astrope@e-corp.net> wrote: > >Hi, I recently took a system in to have the cpu upgraded and the > >components transfered from an atx case to a rack case. When I got home, > >the kernel booted, but e2fsck would just hang. I used a boot/rescue disk > >and tried running e2fsck manually and it hangs again, but not before > >outputting the following messages: > > > >/dev/sda1 was not cleanly unmounted, > >check forced > >pass 1, checking inodes, blocks and sizes > >scsi: tagged queuing now active for target 0 > > > >Then nothing. Does anyone know what might be causing this? Could it just > >be that the scsi disk wasn't connected properly? All my partitions show up > >with fdisk and the scsi bios detects the Seagate drive when the scsi bios > >is scanned... Also the kernel boot messages show that the disk is detected > >at scsi0. > > > >Any help is appreciated. > > Sounds like you might be missing the termination now, or the cable got > pinched and is now bad in some way. It definitely sounds like a > cabling/termination issue... They could have connected the drives with the terminated one not at the end of the cable, or there might be no device at the end of the cable which is just as bad. Maybe they were thinking of IDE... === Subject: Anyone had problems with SCSI HD >= 18 GB? From: "Steve \"Stevers!\" Coile" <scoile@redhat.com> Date: Thu, 17 Jun 1999 12:17:15 -0400 (EDT) I've received several reports from folks having difficulties using 18 GB and larger SCSI hard drives. These folks *must* partition the drive: a single, large partition will not be recognized by Linux. Has anyone experienced this? Anyone know anything about it? === Subject: Re: large SCSI HDs (>18G) From: Ron Golan <rgolan@coalabs.com> Date: Thu, 17 Jun 1999 15:16:42 -0700 (PDT) On Thu, 17 Jun 1999, Matt Housh wrote: > > No idea about drives THAT big, as I've only got a 9G, but you > still have to observe the 1024 cylinder limit of the bios. My 9G U2W > reports 1111 cylinders, so I have it partitioned with a small boot > partition for kernels, that fits under the 1023rd cyl... I would assume > that, barring bios incompatibilities, the larger drives would act the > same... I am using a 9.1GB SCSI drive and have some problems with fdisk_v2.9n. When trying the verify command, I am always warned that partitions conflict. This is for any cylinders which cross the 1023 boundary. Looking at the partition table in expert mode shows that fdisk doesn't report cylinders above 1023. Expert command (m for help): p Disk /dev/sda: 255 heads, 63 sectors, 1115 cylinders Nr AF Hd Sec Cyl Hd Sec Cyl Start Size ID 1 80 1 1 0 254 63 2 63 48132 83 2 00 0 1 3 254 63 1022 4819516386300 83 3 00 0 1 1023 254 63 102316434495 1220940 83 4 00 254 63 1023 254 63 102317655435 257040 82 In regular mode the table looks like this Disk /dev/sda: 255 heads, 63 sectors, 1115 cylinders Units = cylinders of 16065 * 512 bytes Device Boot Start End Blocks Id System /dev/sda1 * 1 3 24066 83 Linux /dev/sda2 4 1023 8193150 83 Linux /dev/sda3 1024 1099 610470 83 Linux /dev/sda4 1100 1115 128520 82 Linux swap Although fdisk complained of conflicts, I have seen no problems yet with this Red Hat 6.0 system. === Subject: Re: [OT] Mixing SCSI and IDE drives. From: Rick Forrester <rickf@crow.jpl.nasa.gov> Date: Tue, 26 Oct 1999 06:40:23 -0700 mcamacho@habitat.co.cr said: > Dear friends, I am assembling a new box for myself, and I was adviced > on the computer shop not to mix IDE and SCSI drives. I have been told, > too, that I can only get a better performance of an SCSI hard disk > over an IDE hard disk if I have more than one hard disk. On the other > hand, I want to burn CD's, so, I've been told that SCSI CD-RW work > better than IDE ones. > Now, as I am an "amateur" and you are the "pros" on Computer Science, > I would really appreciate your help on the following: > 1. Can I mix SCSI & IDE disks with "no pain"? 2. Does SCSI CD-RW > really have a better performance than IDEs? 3. Would it make sense to > install an SCSI CD-RW and a SCSI CD-R, and use an IDE hard disk? Hi Manuel, Well, as is all too often the case, the computer shop doesn't know what they're talking about, and dispensed bad information. There may have been problems with some earlier systems, but not recently. My last 4 boxes I've built have had a mix of IDE & SCSI devices in them, using Symbios, BusLogic, & Adaptec controllers without problems. My primary system at home is based on an Asus P2B motherboard (be sure to turn off the SCSI BIOS option in the BIOS when using a card with it's own SCSI BIOS such as BusLogic or Adaptec). It's currently using an Adaptec AHA 2940U2W controller. The IDE side has an IBM 4.3Gb IDE drive as /dev/hda, a Toshiba 36X IDE CD_ROM drive, and an LS-120 drive as /dev/hdb. Over on the SCSI side I've got 2 Seagate ST32350W 2.1Gb SCSI drives, and IBM 18.3Gb U2W SCSI drive, and a Plextor 820 CDR drive. Everyone plays well together. My advice would just be to check the motherboard BIOS options carefully; some mb's have built in SCSI BIOS, which lets them use cards which don't have their own SCSI BIOS to support booting, etc. If your controller has a built in BIOS, then turn off the SCSI BIOS option in the mb BIOS. Check the other BIOS options, especially the boot drive options with care. Be sure you use decent quality (not necessarily expensive) cables on the SCSI side, especially, and be sure your SCSI buses are properly terminated, preferably with active termination in my experience, either by the last device on each chain or with a terminator at the end of the cable. === Subject: Re: [OT] Mixing SCSI and IDE drives. From: Jim Morris <Jim@Morris.net> Date: Tue, 26 Oct 1999 08:52:28 -0500 Hello Manuel, Monday, October 25, 1999, 9:31:03 PM, you wrote: Camacho> Dear friends, I am assembling a new box for myself, and I was adviced on the Camacho> computer shop not to mix IDE and SCSI drives. I have been told, too, that I can Camacho> only get a better performance of an SCSI hard disk over an IDE hard disk if I Camacho> have more than one hard disk. On the other hand, I want to burn CD's, so, I've Camacho> been told that SCSI CD-RW work better than IDE ones. That's hogwash. I've mixed SCSI and IDE on many systems over the years. Both my home PC's use a mix of SCSI and IDE devices. Camacho> 1. Can I mix SCSI & IDE disks with "no pain"? The only possible pain could be that your SCSI controller will require an Interrupt. So if the PC is full of expansion cards, and both IDE channels are in use (they use IRQ 14 and IRQ 15), the availability of a free IRQ could be an issue. Note however that most modern PCI 2.1 compliant cards do a pretty decent job of sharing IRQ's between cards. I've got 4 PC's that use both IDE and SCSI - and a full complement of expansion cards. The one I am sitting at right now has 4 PCI cards (including SCSI), an AGP video card, and 1 ISA cards. Camacho> 2. Does SCSI CD-RW really have a better performance than IDEs? The difference is in CPU usage. IDE interfaces require a lot more work from the CPU to move the data around. A typical IDE CD-ROM drive running full-out can consume possibly 30% of the CPU time on an average desktop system (well - average of maybe a year ago). The same holds true for keeping data going to the CD-RW drive. So if you are on IDE for everything, so much CPU time is required to keep the data moving, that you cannot really use the PC during the process of burning the disc - otherwise, you may cause a drop out. The benchmark comparisons I saw when I was buying a CD-RW a year or so ago showed that a SCSI CD-ROM or CD-RW only consumed about 3% of the CPU on the same system, due to the greater intelligence of the SCSI interface. I.e. the SCSI adapter can DMA data directly into the host's RAM, etc. Most CD-ROM and CD-RW devices do not support the DMA modes of EIDE interface, either. Camacho> 3. Would it make sense to install an SCSI CD-RW and a SCSI CD-R, and use an IDE Camacho> hard disk? That's what I have here - good fast IBM Deskstar EIDE hard drives, and SCSI CD-ROM and CD-RW drives (and one old 2GB SCSI hard disk). For running a CD-RW, you don't need anything beyond something like an AdvanSys SCSI2 or Ultra-SCSI PCI card, which is probably $40-$70. I've used a lot of NCR/Symbios chipset based SCSI adapters too. Camacho> BTW, system is for personal use at home - which means from 10:00 pm to 1~2:00 am Camacho> =). Definitely go SCSI for your CD-ROM and CD-RW - but IDE for the hard drives. It will let you get a LOT more drive capacity for the $$$'s than SCSI hard drives will provide. === Subject: Re: [OT] Mixing SCSI and IDE drives. From: Gregory Hosler <gregory.hosler@eno.ericsson.se> Date: Wed, 27 Oct 1999 08:41:13 +0800 (SGT) On 26-Oct-99 J. Scott Kasten wrote: > Well, there are varying issues here. You can mix SCSI and IDE in a system, > however > it can be a chanllenge due to limited resources such as DMA channels and > interrupts. > Things like soundcards always hog more than their share, and most PCs today > come with > dual IDE controllers on the main board, so there may not be enough left over > to put > that SCSI card in. you don't need to enable both channels if you are not using both channels. > As far as speed, that's a somewhat complicated issue. Here's the simplest > rule of > thumb. If you consider a single drive on a single controller, then a modern > IDE > drive on a modern IDE interface with the more advanced transfer modes turned > on > will be faster than the mid generation SCSI drives (AKA Fast SCSI, SCSI II) > in > terms of bus transfer. However the high end WIDE and ULTRA WIDE SCSI (read > EXPEN$IVE) relatively speaking, your WIDE /UW / LVD scsi will be more expensive than "mid range" scsi, and either will be more expensive than IDE. But the cost increment, these days, is not that great (compared to, for example, the cost increment several to 5 years ago, when scsi was about us$1k per gb) ===