mwatson@nswc-oas.arpa (Mike Watson) (05/12/88)
I use dired (part of Gnu Emacs) to remove files with funky names. It's quick, painless, and will remove (or rename) files regardless of name (in my experience). I have used it to remove files with names on the order of "lpr -q ..." among other things. This may or may not be helpful in your case. Any opinions expressed above are my own. Arpa: mwatson@nswc-oas.arpa Usenet: uunet!nswc-oas.arpa!mwatson _ _ _ _ __ _ ' ) ) ) / /) ' ) ) ' ) / _/_ / / / o _. /_ __. _ // /--' / / / __. / _ ______ / ' (_(_(__/ /_(_(_(<_(/_ / \ o (_(_/ (_(_(__/_)_(_) /) )_
michiel@idca.tds.PHILIPS.nl (Michiel Fierst van Wijnandsbergen) (12/14/90)
In article <1990Dec3.142714.20868@watdragon.waterloo.edu> tbray@watdragon.waterloo.edu (Tim Bray) writes: >There is now good optical disk jukebox technology; a common application is the >storage of millions (literally) of compressed page images; essentially just an >optical file cabinet. Group 4 compressed Tiff format is quite common. > >Recently went looking for somebody who's doing this on a Unix box; shouldn't >be hard, these things have SCSI interfaces. Was rather surprised to find >nothing out there. But here we are!! >Anybody doing this? Better yet, anybody selling tools to automate and control >this process? Anybody at least have a usable driver interface? Ideally for >DEC RISC boxes, but any popular system would be of interest. OK. Here's a story about our product. It is rather lengthy, but it is as dense as possible and still clear for a relatively broad audience. ------------------------------ INTRODUCTION The Philips Megadoc Optical File Server is a server that offers a very large ON LINE storage capacity in NFS networks. It uses Optical storage technology to achieve that, combined with jukebox support, transparent volume management and a file system. The Optical Disk File System takes WORM characteristics fully into account and acts like a normal magnetic disk based file system that has rewritable files and directories. The Optical File Server itself however, does not make any assumptions on the networking interfaces used, so it can be used with any networking solution that is offered by the platform it is running on. PORTABILITY The Optical File Server is portable. Several UNIX platforms are supported. It even runs on a 386 AT platform at the low end! The file server is a software product, that can be sold with hardware to end-users, but does in no way rely on special hardware support. It does not depend on devices or platforms that have been specifically adapted for this optical file server, but runs on standard available hardware. COMPONENTS The file server software consists of three main components: ODFS, the optical disk file system VM, transparent volume management device drivers The ODFS takes care of files, caching on magnetic disk and recovery features. Its user interface is the UNIX file interface and behaves to the user as any normal rewritable magnetic disk based file system. Volume Management takes care of transparently loading the actual disks on drives when requested. It also controls the jukebox when present. Device drivers implement device dependent functionality, to make devices available for the other software layers. Drivers included in the optical file server product are drivers for optical disks and jukeboxes. These main components are independent of each other. This means that the drivers can be used without the rest of the software, the ODFS only needs the optical disk driver(s) to be present and VM only needs the jukebox driver. ODFS can be used on systems without VM. VM can be used on systems without ODFS. ODFS: PORTABILITY The optical disks file system is implemented using standard UNIX in-kernel interfaces, such as the File System Switch in UNIX System V.3.2 and VFS in SunOS. It is therefore easily portable to other UNIX flavours. UNIX System V.4 is planned for 1991. ODFS: FLEXIBLE CACHING AND TUNING ODFS makes extensive use of caching, both in core as well as on magnetic disk. A magnetic disk partition is always assigned to one or more Optical Disk File Systems. The system can be set up in a very flexible way by assigning magnetic disk partitions of various sizes to groups of optical disk file systems. This allow the system administrator to tune the server in such a way that the most frequently used optical disk file systems have the largest cache space. This kind of tuning is not required when absolute top performance in not an issue; the system will automatically balance on the optimal use of cache space, depending on the requests that have been made to it. ODFS: RECOVERY The recovery of the caching system is fully supported in case of power failures etcetera. A lot of effort has been put in the ability to reconstruct the cache from the optical disks to protect the user against magnetic disk crashes. ODFS: TRANSPORTABILITY Optical disks containing file systems can be transported to other servers easily, since optical disks can be handled as independent, self contained, media. They contain complete file systems that do not rely on other optical disks, thus preventing mistakes that would be made when a complete set of disks would have to be transported in a fixed order. ODFS: STANDARD USER INTERFACE Since the Optical Disk File System completely adheres to standard UNIX kernel interfaces, there is no special interface to access files. ODFS behaves like any standard UNIX file system. Once mounted, files can be accessed with the normal UNIX system calls. This means that all applications using the standard system calls will run on ODFS without change. This is also true for the UNIX commands itself. ODFS comes with a small number of specific utilities for maintenance and setup. ODFS: INDEPENDENT The ODFS can be used independent of volume management, but it relies on at least one optical disk driver being present. ODFS has no dependencies on the magnetic disk subsystem, as long as it is present. VOLUME MANAGEMENT: TRANSPARENCY The Optical File Server is meant to operate in an environment where large volumes of data have to be stored on optical disks. As optical disks are removable media, there is no fixed relation between the disk and the drive on which the disk is loaded, like there is for magnetic disks. As a consequence, it is not possible for application programs to access the physical drive, because they have no way to be sure that the right disk is loaded on it during the accesses. To overcome this, Volume Management offers the concept of volume devices. When application programs access these volume devices, i.s.o. the physical devices, Volume Management takes care that the corresponding disk is loaded on a drive and routes the access to the selected drive. In this way Volume Management offers complete location transparency. Volume Management supports stand-alone drives and drives contained in jukeboxes. In the first case, operator action is required to load/unload disks; in the second case the loading/unloading is performed completely automatic in a way which is optimized towards high throughput and low response times. When Volume Management is combined with the Optical Disk File Systems, applications can access files on mounted file systems. ODFS will use a magnetic disk cache as much as possible, but when an actual I/O to Optical Disk is needed, Volume Management will automatically load the requested disk. DEVICE DRIVERS: STANDARD INTERFACES The device drivers supplied with the file server are the software modules that allow the rest of the system to work with the specific optical filing peripherals. They completely obey the standard UNIX interfaces for drivers. Access to drivers is possible via standard UNIX nodes in /dev. Device drivers are available for a wide range of devices. To support other devices, new device drivers can be easily added and integrated into the system. The device drivers may be used independent of the other software components of the optical file server. HARDWARE: OPTICAL DISKS Several Optical disk drives are supported, currently all from LMSI: LD510 5.25" WORM LD520 5.25" Multi Function (shortly) LD1200 12" WORM 2GB LD4100 12" WORM 5.6GB (shortly) LF4500 12" WORM Rapid changer 5x5.6GB = 28GB (shortly) The LF4500 is a device constructed around the LD4100 drive. It is a disk changer containing 5 disks, but it acts like a single device. It is in fact a small 12" jukebox with a single drive as an integral part of it. The disk change times are very short as compared to conventional jukeboxes (4s for any disk replacement) HARDWARE: JUKEBOXES A number of jukeboxes are supported: IDE, 10 disks, 1 drive, 5.25" (shortly) HP C1710A (as LMSI's LF512), 32 disks, 2 drives, 5.25" FileNet OSAR-64, 64 disks, 4 drives, 12" FileNet OSAR-200, 204 disks, 4 drives, 12" FileNet and Cygnet are considered for the LD4100 There are no plans for support of other drives and jukeboxes, but there are no technical objections. The hardware mix mentioned above is what Philips selected for their own sales. The software is layered in such a way that support of other devices is easily added. This means that all hardware depedencies are grouped together in as few modules as possible. MORE INFORMATION For more information contact me at: email: fierst@idca.tds.philips.nl or hp4nl!philapd!fierst fax: xx31 55 43 3488 mail: M. Fierst van Wijnandsbergen OFS - BK P.O. box 245 7300 AE Apeldoorn the Netherlands Europe ------------------------------ -- # Michiel Fierst van Wijnandsbergen Internet fierst@idca.tds.philips.nl # # Philips Telecomm. and Data Systems UUCP ...!mcvax!philapd!fierst #