HP 3000 Manuals HP 3000 Manuals
Chapter 4 PERIPHERALSUPPORT Eagle/AMUX Disc: 7937FL by Chris Hugins, Information Software Division Hewlett-Packard introduces the Fiber-Optic version of its Eagle disc drive. The HP7937FL Eagle/AMUX Disc is the same high performance, large capacity disc drive as the HP7937H with the replacement of the HP-IB (1 Megabyte/second) interface with the new, high speed fiber-optic ALINK/AMUX (5 Megabytes/second) interface. Those characteristics inherent to the HP7937H disc mechanism (access time, latency, etc.) are identical. The increased bandwidth over the ALINK fiber-optic interface does increase the connectivity of devices per Device Adapter card. Additionally, the cable-length allowed between system and device is considerably greater. HP7937FL Eagle/AMUX Features The features of the HP7937FL Eagle/AMUX which differentiate it from the HP7937H disc drive is attributable to the ALINK/AMUX hardware interconnect. Fiber-Optic Benefits The ALINK is a high speed serial fiber-optic data link which is totally immune from the effects of Electrical-Magnetic Interference (EMI). Additionally, the fiber cable is thin and light, and may be extended up to 500 meters with no ill effects. Connectivity Up to eight (8) HP7937FL Eagle/AMUX disc drives may be connected to each ALINK Device Adapter (HP27115). This is due to the increased bandwidth which the ALINK/AMUX is capable. Product Identification This device may be identified by the use of the :DSTAT command. The :DSTAT output displays "079370" for the HP-IB Eagle disc, and displays "07371" for the ALINK Eagle/AMUX disc. Data Integrity The HP7937FL Eagle/AMUX utilizes many levels of Parity, Cyclic Redundancy Checking, and Error Correction Code throughout the entire subsystem. Automatic Rotational Positional Sensing The HP7937F Eagle/AMUX always performs an optimal Rotational Positional Sense (RPS). The user has no need to execute the :DISCRPS command. FLEX Instruction Set The FLEX Instruction Set is used by the HP7937F Eagle/AMUX to better support the new features of this new disc subsystem. Much of the instruction set is identical to the CS80 Instruction Set. A new manual is available defining these FLEX device instructions, the FLEX Instruction Set Programming Manual (P/N-5959-3909-1). Bad Sector Sparing The HP7937FL Eagle/AMUX disc subsystem, in conjunction with the Eagle/ AMUX Disc Device Manager (MPE XL device driver), performs "sparing" of marginal and/or unrecoverable data due to media defect ONLINE. The HP7937FL Eagle/AMUX disc subsystem performs all necessary functions required for this operation automatically, upon receipt to the SPARE Retaining command. This includes saving even the problematic data! The device automatically performs an Error Rate Test on the sector in question to verify the media, and restores ALL the data to an appropriate sector. For MARGINAL data detection, this feature is especially beneficial. In this case, the data has been recovered so it is good. ONLINE Sparing eliminates further degradation because the data is moved, intact, to good media before any loss can occur.