RIM Crippling BlackBerry Bluetooth Speed? 96
Alex King writes " I organized a bounty for the creation of a 'BlackBerry as a modem' solution for Mac OS X earlier this year. The resulting product — Pulse, from Brain Murmurs — allows you to use your BlackBerry as a standard Bluetooth modem. It works great on both Windows and Mac. Current problem: The Pulse solution doesn't run as fast as it used to. Brain Murmurs did a bunch of testing and working with their users and found the problem: RIM has crippled the Bluetooth speeds in recent OS upgrades. Is this a 'mistake' on RIM's side that will be fixed? Or did they do this on purpose for some reason?"
Re:Thats just silly (Score:1, Informative)
Your crap about modulation modes is irrelevant; after an 'upgrade' to the blackberry software suddenly the throughput through the stack is a lot less. The fact that there are a limited quanta of symbol rates over the air does not preclude limiting application layer performance through a variety of means, intentionally or unintentionally.
Re:Why not open source the software? (Score:4, Informative)
It was a pretty small bounty -- $675 -- and I think he lays out his reasoning quite cogently in this blog post [alexking.org].
Re:Why on earth would RIM want you to do this? (Score:3, Informative)
Wow.. this is so wrong:
As other replies have mentioned, CDMA stands for Code Division Multiple Access. Each packet is tagged with a small code similar to the way ethernet packets are tagged with a MAC address. GSM is a TDMA system (Time Division ...) which relies on phones transmitting in an allotted time slot (milliseconds). This could be likened to a token ring network in some ways
That is bad enough but then you go on to state that it's not like a cable modem link. Huh? It is exactly like a cable modem link. In fact, just about any network or bus, wired or wireless, uses some sort of scheme to allow for multiple transmitters. In DOCSIS you have both a MAC (code) as well as an allotted time slot. DOCSIS takes it a bit further and does ranging. Basically, it pings the node at the head end until it gets an accurate picture of how long an electrical signal takes to reach the node. This allows the cable modem to adjust its transmissions such that when it transmits in a given timeslot it won't collide with another modem's time slot due to signal delay differences. The speed of electrons is after all only so fast.
I could go on and on here by pointing out that for example a T1 line is actually 24 time divided channels or that a PCI bus works on an acquisition basis. Next time before calling the parent poster a dorkwad (what are you 11?) you might actually want to know what you are talking about.