[iBook] Yet another problem...

[Fred Stevens K2FRD]

I'm not a computer or other design engineer, but I am a radio systems engineer and am cognizant that any design which did not allow for memory retention was flawed. In the "early days" of EEPROMs, the chips which were engineered to replace memory batteries were not very good and seldom met design specifications. In other words, they failed after only a few days or few weeks leading operators to believe that no memory backup had been installed when in fact an EEPROMs was there, but just didn't work. The only way to retain system memory was to switch main batteries VERY QUICKLY before the RC circuits fully discharged.

My most personal example of this was a Uniden two meter ham radio rig purchased in the early 1990s. When it suddenly went to flashing display digits every time it was turned on, we went looking for the memory battery and couldn't find it in the schematic. It didn't have one because it had an EEPROM which, primitive as it was, failed. There was no means to reprogram nor recharge it, so the radio went the way of the Dodo and used microwave dinner plates. While an EEPROM can in theory be replaced, it isn't very practical and, at least on older machines, would cost more in labor and agony costs that it was worth. Thankfully, those days are over and new machines have reliable EEPROMs.

Fred

At 11:44 PM -0400 6/3/06, Brian Pearce wrote:
>>I'm not an expert on clamshells, but given clamshells are older Mac laptops (seven years? Ten years?), I would guess that they have wafer (i.e., real) batteries) to maintain all settings including the clock.
>
>If I'm not mistaken, the clamshell iBooks had no logic board battery, nor other source of power to maintain settings -- they were completely dependent on the iBook battery. If the power was completely disconnected, settings were completely erased (and the clock was reset to "1904"). I had this happen once with a Tangerine iBook -- I don't think it ever happened with my Key Lime iBook.
>
>(Pat was referring to a G4 Powerbook, though.)

-- 
73 de Fred Stevens K2FRD, VO2FS
http://homepage.mac.com/k2frd/K2FRD.html