ZIP-drive mini-HOWTO Grant Guenther, grant@torque.net v1.0, 15 April 1996 The Iomega ZIP drive is a popular, removable media disk drive. It is available in two main versions, one has a SCSI interface and the other connects to a parallel port. This document describes how to use the ZIP drive with Linux. It should be read in conjunction with the SCSI HOWTO. 1. Introduction The Iomega ZIP drive is a popular, low-cost, low-performance, portable, removable media disk drive. Its disks have a capacity of 96 megabytes, and the drive is available in two main versions, a SCSI version and a parallel port version. The parallel port version is actually a SCSI device as well, configured to use Iomega's proprietary PPA-3 SCSI-over-parallel protocol. This document describes how to use the ZIP drive with Linux. Since this is a SCSI device, it is important for you to read the SCSI HOWTO as well. That document gives a thorough introduction to the Linux SCSI system. It does not contain any specific information about the ZIP drive, the ZIP Zoom SCSI host adapter or the PPA-3 parallel-to- SCSI adapter. This mini-HOWTO aims to fill those gaps. This document incorporates information collected and published by others, in particular: · Scot Wilcoxon, sewilco@fielday.mn.org · Joe Mack, mack@ncifcrf.gov · Byron Jeff, byron@cc.gatech.edu I thank them for their important contributions, and accept responsibility for any errors that I have introduced. 2. The ZIP drive There are three versions of the Iomega ZIP 100 drive. They all accept special cartridges resembling a 3.5" floppy disk that hold 100 megabytes of data. The disks actually hold 96 cylinders of 2048 sectors each holding 512 bytes. This would normally be called 96 Megabytes. One version is a half-height 5.25" internal drive, with a SCSI interface, the other two are external drives in a small blue lightweight plastic enclosure, powered by an external wall brick. The external drives come in a SCSI version and a parallel port version. All the drives have a large pushbutton on the front of the drive. This is used to eject the disk. Linux locks the door while using the drive, but if the button is pressed while the door is locked, the ZIP drive will remember and eject the disk as soon as the software unlocks it. 2.1. SCSI version The external SCSI version of the ZIP drive has two DB25F connectors, and two configuration switches. One switch selects the drive's target address: the choice is limited to target 5 or 6. The other enables an internal terminator, in case the drive is the last one on a chain. The 25 pin SCSI connectors use the familiar Macintosh style wiring. The drive is shipped with a Macintosh type cable, but standard cables and converters are easily obtained if you are using a host adapter with a Centronics or high-density connector. I have not seen an internal SCSI drive, but I would expect it to have a standard 50 pin DIP header SCSI connector and the same two switches. Make sure that the target address you choose does not conflict with any other SCSI devices you may have on the same bus. Also be sure that the physically last drive in a chain has termination enabled, or an external terminator installed. If you have an internal SCSI disk or CD-rom, and you connect your ZIP drive to the existing adapter, you should check to see if there are any terminators on the card that must be removed. Only the two extreme ends of the SCSI bus should be terminated. If your bus is partly internal and partly external, there should be one terminator on the last external device and one on the last internal device, but no terminators on the adapter card itself. Be sure that all cables are firmly attached. 2.2. The ZIP Zoom host adapter Iomega markets a SCSI host adapter under the name ZIP Zoom. This is actually based on the design of the Adaptec AHA1520 family of adapters. It has an external Macintosh type DB25F connector, compatible with the cable that comes with the ZIP drive. Linux supports this adapter with the aha152x driver. 2.3. Parallel port version The parallel port ZIP drive also has two DB25 connectors, the male (DB25M) should be connected with the supplied parallel cable to your computer's parallel port. The other (female, DB25F) is intended to support a chained printer. Linux does not currently support simultaneous use of both a ZIP drive and a chained printer. A work- around is possible using loadable modules. There are no configuration switches. The parallel port ZIP drive is compatible with several types of parallel ports, but currently the Linux driver supports only the Standard and bi-directional ports. If your parallel port has configuration switches (in hardware or on a CMOS setup screen) be sure to set the port into one of those two modes. Be sure that all cables are firmly attached. 3. Configuring a kernel for the ZIP drive To use the ZIP drive with Linux, you must have a kernel configured with support for the SCSI system, support for SCSI disks and support for the host adapter you are using. If you are not familiar with building a kernel, you should go to /usr/src/linux and study the README file found there. There is also useful information in the Documentation subdirectory in recent versions. You must begin the process of building a kernel with the configuration step. Here, you identify the specific kernel components that you need. make config is the traditional, sequential, question and answer method of configuring the kernel. In recent kernels there are some new alternatives: make menuconfig does the same thing with a menu oriented interface, and make xconfig uses the tk toolkit to provide a version that is nice to use under X. Once you have configured your kernel, use make dep and make zLilo (or make zImage if you don't use LILO) to compile the new kernel and install it. And, of course, don't forget to shutdown and reboot ! You can also build all or part of the SCSI system as modules. If you do this, be sure to load scsi.o, then sd.o and finally the driver for your host adapter, before you try to access the ZIP drive. 3.1. SCSI version If you already have a SCSI disk in your system, and you are connecting the ZIP drive to the same controller, there is no additional kernel configuration required. Otherwise, you will most likely have to build a new kernel. If you are building a kernel to support the SCSI version of the ZIP drive, you should select SCSI support and SCSI disk support. You must also select a driver for the interface card you will use. If you have a ZIP Zoom, select the aha152x driver. Be sure to read the documentation for your adapter in the SCSI HOWTO and any README files in the drivers/scsi subdirectory of the Linux source tree. Pay attention to command line parameters that you might have to use to help the kernel initialise your adapter. For instance, if you are using the ZIP Zoom card, you will have to add something like aha152x=0x340,11,7,1 to the boot command (or include it in your /etc/lilo.conf file in an append clause). This tells the driver the port address and IRQ of your ZIP Zoom card - be sure to use the numbers that correspond to the way your jumpers are set. You should also read Paul Gortmaker's BOOTPROMPT HOWTO for information about configuring your kernel with LILO or LOADLIN. 3.2. PPA driver for 1.2.13 If you want to use the parallel port ZIP drive with the stable kernel, version 1.2.13, you must fetch version 0.18 of the driver which is available for anonymous ftp at Installation instructions about how to compile the driver as a loadable module are contained in the source for ppa.c. Please note that you will almost certainly have to build a new kernel. In particular, none of the Slackware pre-built kernels will work with ppa. Be careful to build your kernel with SCSI support and SCSI disk support, but do not include support for the lp printer driver. In 1.2.13 the two drivers cannot co-exist in the same kernel. You can adjust the port number and some timing parameters on the insmod command line when you load the ppa driver. These adjustments are documented in the ppa.c file. By default the driver assumes that the ZIP drive is connected to the parallel port at 0x378. There will not be any enhancements to this driver for the 1.2.13 kernel. You should expect it to disappear a few months after the 2.0 kernel is released and the major distributions start using it. 3.3. PPA driver in current kernels Since version 1.3.74 the ppa driver has been a standard part of the kernel. There were some changes to other parts of the kernel around 1.3.78 that required an interim workaround, but since 1.3.85 the driver has been quite stable at version 0.26. Since the code-freeze for Linux 2.0 is now in effect, I expect that 0.26 will be in the next stable kernel. To build a kernel with ppa support, include SCSI support, SCSI disk support and select the Iomega ZIP / PPA-3 support from the list of low-level SCSI adapters. You can also build the driver as a loadable module. You can use command line parameters in /etc/lilo.conf or with insmod to adjust the driver. This is all documented in drivers/scsi/README.ppa in the kernel source tree. I've included a summary in the next section. If you want to use both the lp and ppa drivers on the same parallel port, you must build both as loadable modules and load one or the other at any point in time, but not both. Linux's loadable module features are becoming more powerful, and correspondingly more complex, every day. You should read the file Documentation/modules.txt in the kernel source tree, as a starting point. 3.4. PPA command line parameters If you have ppa built into your kernel, you can adjust its parameters from the command line of LILO or LOADLIN with the following syntax: ppa=base[,speed_high[,speed_low[,nybble]]] Where base is the i/o address of your parallel port, speed_high is a timing constant for certain fast loops in the driver, speed_low is a similar timing parameter for some slower loops and nybble is a flag to force the driver to use 4-bit, or nybble mode, even if it wants to do otherwise. For an example, the defaults could be specified as: ppa=0x378,1,6,0 4. Using the ZIP drive If you have built in all the required components, the kernel should recognise your adapter and drive at boot time. If you are using a loadable module for your driver, the following discussion applies once that module is loaded. For the most part, the SCSI and parallel versions of the drive behave identically, except that the parallel version is somewhat slower. 4.1. Identifying the drive at boot time When your system boots it should display several pieces of information about your adapter, your drive and the disk in the drive. If you do not have a disk in the drive, some of this information will be missing and will only appear when you insert a disk and then touch the drive (make some attempt to access it). Beginning users are advised to boot their system with a disk in the drive - things are less confusing that way ! Exactly where these messages will appear depends on how your system is configured. Often they will be displayed to your system console, but they may be diverted into a log file such as /var/adm/messages. Usually, you can retrieve the last couple of screens of kernel messages with the dmesg command, if you can't find them anywhere else. If you need to get someone to help you with anything, a copy of this log information is critical. Try to send as many of the relevant log messages as you can along with any bug report. Here is a sample of what the kernel's log messages should look like: scsi0 : PPA driver version 0.26 using 8-bit mode on port 0x378. scsi : 1 host. Vendor: IOMEGA Model: ZIP 100 Rev: N*32 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sda at scsi0, channel 0, id 6, lun 0 scsi : detected 1 SCSI disk total. SCSI device sda: hdwr sector= 512 bytes. Sectors= 196608 [96 MB] [0.1 GB] sda: Write Protect is off Partition check: sda: sda1 This output came from a 1.3.87 system with a parallel ZIP drive. The exact output will vary depending on your host adapter and whether you have any other SCSI devices in your system. The first line displays the initialisation message from the low-level driver for the host adapter, in this case PPA. Following that comes the drive identification information returned by each device found on the SCSI bus. Line 5 reports the device name assigned to the drive, in this case /dev/sda. And the last line hows the result of the partition check of the disk in the drive. This one has one partition,/dev/sda1. These reports come from different modules in the kernel, if you have more than one SCSI adapter, or several disks, each section will contain more information. If you are using a fresh disk, direct from Iomega, the partition check should show one partition, /dev/sda4. If you have other SCSI devices you will understand that the ZIP drive could appear on some other device name like /dev/sdb - so check these messages. If these lines do not appear, then something is misconfigured in your hardware or in the kernel. Check everything carefully before sending mail. If the scsi0: line does not appear, then you have not configured your host adapter and its driver correctly. Some drivers will give you a hint about what is wrong. If your drive is not detected, you probably have a cable problem. If a drive name is not assigned, you probably forgot to include SCSI disk support when you built the kernel. Check the README files in drivers/scsi and the SCSI HOWTO for other debugging hints. 4.2. Fdisk, mke2fs, mount, etc. Once you know the drive name for your ZIP drive, you are set. You can manipulate the drive with the normal Linux disk management commands. fdisk (or perhaps cfdisk) is used to manipulate the partition tables on the disk. mke2fs can be used to format a partition with the ext2 filesystem - the one most commonly used in Linux. mount is used to connect a formatted partition into your directory hierarchy. You should study the manual pages for these tools if you are not familiar with them. Be warned that there are now several quite different versions of the fdisk program - be careful. I'll describe two common scenarios. 4.2.1. An existing DOS formatted disk If you have a ZIP disk with a DOS file structure that was originally created by Iomega's tools, the partition scan should say that the disk has one partition, /dev/sda4. You should make a place to mount the disk, lets say /zip, and then mount it as an MS-DOS filesystem: mkdir /zip mount -t msdos /dev/sda4 /zip Now, the files on the disk should appear in /zip. While the disk is mounted, you will not be able to remove it. When you are finished with the disk you can umount it to release it and detach it from your directory hierarchy. umount /zip Once you've made the /zip mount point - you don't need to do it again, so you could come back later and mount something else there. 4.2.2. Re-format as a native Linux disk If you want to erase a ZIP disk and make a Linux native file system on it. you should use fdisk on the entire disk: fdisk /dev/sda and delete any existing partitions (with the d command). Then create a new partition with the n command, make it primary partition number 1, use w to write the partition table to disk, and quit with q. Format the partition mke2fs /dev/sda1 (The 1 is the number that you gave this partition in fdisk). Now you can mount the disk: mount -t ext2 /dev/sda1 /zip (re-using that mount point we created before). 4.2.3. The ZIP Tools disk There is some extra work to be done if you want to use the disk that comes with the ZIP drive. As shipped, the software controlled write protection is enabled. Most people have unlocked the disk under DOS before ever trying to use it with Linux. Linux cannot access a locked disk, and it must be unlocked with Iomega's tools. A native Linux program to manage the write protection feature, among other things, is expected to be available soon. 4.3. Ejecting a disk You can only eject a disk when it is dismounted. Currently, there is no Linux command to eject the disk, so you must press the button on the front of the drive to eject the disk. Linux ensures that all data have been written to the disk before it is unlocked. Watch for a new ZIP tools program for Linux which will support some of Iomega's special features (including software controlled ejection and write protection) on both the SCSI and parallel versions of the drive. 5. Frequently asked questions These are some of the questions that we get asked a lot. Please read the answers here before asking them again ! 5.1. Can I boot from the ZIP drive ? This depends on what you are using for a host adapter. If your host adapter has a BIOS ROM with code that can boot from target 5 or 6, then yes, you can boot from the SCSI ZIP drive. You cannot boot from a parallel port drive. If you have DOS on your main disk and want to boot Linux from a ZIP disk, you can do this using the LOADLIN boot loader. Your kernel image must be somewhere on the DOS disk, but the rest of your Linux system could be on the ZIP. Make sure that the kernel you use has the correct drivers built in. As far as I am aware, there are no installation boot floppies for any of the popular distributions that contain the parallel ZIP driver, but this may change when Linux 2.0 comes out. 5.2. Why does Iomega use partition number 4 ? This is one of the most popular questions, but I don't think anyone has a definite answer to this one. Maybe there is no good reason. 5.3. How can I have the disk mounted at boot time ? All you need to do is to add a line to your /etc/fstab file. For instance, if you will always have a DOS disk in the drive when you boot, you could put /dev/sda4 /zip msdos defaults 0 0 in the fstab. Depending on your distribution, the initialisation scripts might try to run fsck on partitions listed in your fstab. Be aware that this could cause problems if you forget to put the disk in the drive when you boot, or have the wrong disk there. 5.4. What happens if there is no disk inserted when I boot ? The kernel will try to read the partition table, but the operation will time out. There is nothing to worry about. Once you have inserted a disk, and try to do something with it the kernel will notice that there is a disk there now and rescan the partition table. HINT: when you change disks, it is a good idea always to use fdisk to check the partition structure on the new disk. The BIOS on some SCSI host adapters will attempt to read the partition table on your disk during the system boot. If you cannot disable this check, you may be forced always to boot with a disk in the drive. 5.5. What SCSI adapters are compatible with the ZIP drive ? Iomega has a list of compatible host adapters at: 5.6. Can I use the parallel drive as a real SCSI disk ? The PPA-3 parallel-to-SCSI adapter is implemented as a single ASIC chip that Iomega calls a VPI0. It is embedded on the ZIP drive's controller card. There is an actual SCSI bus present, but not in a useful form. Although I haven't tried to compare the two cards, it seems logical that the VPI0 replaces the conventional electrical buffering circuits that would be required if the SCSI bus were extended outside the package. 5.7. Can I plug a printer into the parallel drive ? Yes, but. Currently, you cannot have both the lp and ppa drivers active on the same parallel port. A resource sharing protocol has been designed and is in the early stages of implementation, but will not be available before Linux 2.0 is released. In the meantime, if you do chain a printer and a ZIP drive, you can use them both without rebooting your system, providing you have built the lp and ppa drivers as loadable modules. If you have done so, then when you want to print you would insmod the lp driver, and when you want to access the ZIP drive you would load the ppa driver. Of course, if you have two parallel ports, you can use one for printing and one for your ZIP drive. Just build a kernel with both the lp and ppa drivers included, then put some appropriate configuration commands on your kernel command line. For instance, if you use LILO and you have a printer on 0x378 and a ZIP drive at 0x3bc you could add the following line to your /etc/lilo.conf file. append = "lp=0x378 ppa=0x3bc" 5.8. Do you plan to support EPP/ECP ports in PPA ? ppa was initially developed without the benefit of any technical specifications for the command protocol on the parallel bus. Instead, the DOS emulator was used to gather information to reverse engineer the protocol. It was not possible to get the drive to work in an enhanced mode under the emulator. An Iomega technical reference manual is now available, and I have located a data sheet for an enhanced parallel port chip, so it may be possible to upgrade the driver. 5.9. Can PPA be used with Iomega's parallel port tape drives ? No. Those drives are floppy-tape drives, there is no SCSI involved. Several people have indicated an interest in applying my methods to try to determine the protocol and develop a driver for these tapes. The first step in that process is to get the DOS driver working under DOSemu. I have not yet heard that anyone has been successful in doing it. 5.10. Will PPA work with the parallel port SyQuest EZ135 ? No. The EZ135 is an IDE drive with a ShuttlePort parallel to IDE converter embedded in it. Work has begun on decoding the protocol with the intention of writing a Linux driver for the parallel port EZ135. I have the basic protocol worked out, but I have no idea when a driver might be completed. Keep an eye on my web page , I will eventually be looking for some beta testers. 6. Getting more current information I will try to keep an up-to-date version of this mini-HOWTO available on my web pages. You can check it out at . There is a more general ZIP FAQ web page (with a definite Macintosh bias) at . Iomega's web pages are at . And if you are looking for general information about parallel port programming for the PC, you might want to visit