Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!rutgers!sri-unix!hplabs!cae780!tektronix!reed!psu-cs!qiclab!neighorn From: neighorn@qiclab.UUCP (Steven C. Neighorn) Newsgroups: comp.sys.ibm.pc Subject: Re: Parameter Ram Backup Needed Message-ID: <418@qiclab.UUCP> Date: Tue, 17-Mar-87 00:36:53 EST Article-I.D.: qiclab.418 Posted: Tue Mar 17 00:36:53 1987 Date-Received: Sat, 21-Mar-87 04:48:16 EST References: <910@hropus.UUCP> Sender: neighorn@qiclab.UUCP Reply-To: neighorn@qiclab.UUCP (Steven C. Neighorn) Distribution: comp Organization: Qic Laboratories, Portland Oregon Lines: 48 In article <910@hropus.UUCP> spj@hropus.UUCP (Stephen P. Johnson) writes: >I recently purchased an AT clone, which has four penlight batteries >inside. My friend says this is to backup the parameter ram which >stores the hard disk partitioning info, amoung other things, and that >when the batteries are removed for replacement or just plain run down, >I will lose the ability to access my hard disk. > >Are there any programs or known methods for backing up and reloading >this parameter ram after the batteries are replaced? > >Steve Johnson (201) 615-4980 Many PC clones come with penlite batteries glued to the power supply instead of a battery pack on the motherboard. They are a bit easier to replace and you can steal them from your camera flash or radio if the computer set runs down. The batteries are used to power the cmos RAM that contain several paramters in the PC/AT system: These paramters are: Time, Date, Type of Floppy disk drive for A:, Type of Floppy disk drive for B:, Hard disk unit 0 type, Hard disk unit 1 type, Type of display (mono, 80 column color, 40 column color, or special, ie ega), amount of memory below 1meg (640k for DOS), and amount of memory above 1meg (extended memory in the AT accessible by unix, xenix, vdisk /E, and disk caches). If you remove the batteries from the system, after a few seconds the cmos RAM will revert to system default values, which are: Drive A: High Density, Drive B: None, Hard Drive Unit 0: none, Hard Drive Unit 1: none, Display type is read from a switch on the motherboard, and memory is set to what the system detects. The reason you lose access to your hard drive is not that you lose partition information on the drive, that is stored *on* the drive. Since after battery power loss, the drive unit types are set to 0. The system doesn't think you have *any* hard drives. All you have to do to regain access to your hard drives is replace the batteries, and run any of numer of setup programs, IBM's original AT setup disk included. If the clone is worth its salt, it should boot IBM's disk. Most clone packages I have seen come with their own (usually better) setup programs. Remember after changing cmos information, you must reboot the system for the new settings to be usuable. -- Steven C. Neighorn tektronix!{psu-cs,reed}!qiclab!neighorn Portland Public Schools "Where we train young Star Fighters to defend the (503) 249-2000 ext 337 frontier against Xur and the Ko-dan Armada" QUOTE OF THE DAY -> 'Dr. Ruth is no stranger to frictionapa