Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!news.cs.indiana.edu!ethome.et.iupui.edu!ethome.et.iupui.edu!mike From: mike@flame.et.iupui.edu (P. Michael Haffley) Newsgroups: comp.periphs.scsi Subject: Re: WangDAT/Dilog compatability Message-ID: Date: 12 Nov 90 18:45:59 GMT References: <1612@camex.COM> Sender: usenet@ethome.et.iupui.edu (USENET News System) Organization: /home/epoch/users/mike/.organization Lines: 36 In-Reply-To: ayk@camex.camex.com.COM's message of 1 Nov 90 15:07:27 GMT The problem is not with Drives, but with the Device Drivers you are using with the drives. Both Drives follow the DDS format, but not all device drivers do. For example, the tape device driver that comes with SunOS 4.1 does not support the 4mm DAT Drives, but one can still hook up the some DAT Drives and use the st device. Since the 4mm DAT Drive is not supported, Sun's device drives reverts to the default Quarter Inch tape format, which uses only 512 byte block size. The DAT Drives by default use 1024 byte block size and can automatically switch the block size that tape had been writen for. Sun's device driver will always force 512 byte block size even if the tape had been written at 1024 byte block size. Thus, a tape written using a device driver especially for the the DAT drive will perform optimally and write 1K block size, but the tape can not be read by the same DAT drive using Sun's st device because it will only try to read at 512 byte block size and fail. Since Sun does not officially support the DAT drive, I would not use the SCSI tape device driver supplied by Sun with a DAT Drive. _ __ _ _ _ _ _ , _ ' ) ) ' ) ) ) / // ' ) / /) /) // /--' / / / o _. /_ __. _ // /--/ __. // // // _ __ , / o / ' (_<_(__/ /_(_/|_ /> / /> /