-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter Maersk-Moller Sent: 24. kesäkuuta 2004 16:01 To: Irek Defee Cc: [EMAIL PROTECTED] Subject: [linux-dvb] Re: More than 4 DVB cards - again
>You mean in practice you can expect to transmit a maximum of 2x400Mbps >over the PCI bus ? it will of course depends on the way the PCI bus >is used. There are many modes of transfer over the bus. I mean you can send from a device to the network 400 Mb/s. I am not based on speculation here. We were doing in the past experiments in transferring data form disk arrays and RAMdisk to Gigabit Ethernet network. This number was obtained for 32bit/33MHz PCI bus, different transfer modes were not significant factor. >One other thing, the PCI bus is no longer the only mean of transfer >data externally. I'm using HS USB2.0 ports to off-load data onto >encoder machines. On some motherboards the on-board usb chip >shares the bandwidth limitation of the PCI-bus, on some they >DON'T. Furthermore, there are motherboards with network adapters >and other adapters included in the North-bridge with direct access >to RAM instead of connected through the south-bridge. There >are also motherboards with more than one PCI-bus. This is true, there are more advanced architectures which could provide more output. Even going to faster PCI buses: 66 MHz doubles the throughput and 64-bit doubles it again. >I have one here with 5 slots, but I have a problem getting more than >4 receivers as mentioned in the beginning of the thread. It is strange that this issue has been downgraded comparing to kernel 2.4. For me it’s a huge factor not to upgrade to 2.6:). But I would suggest to developers to take this into account and provide direct plug-and-play support for more than 4 cards. 6 PCI slots is the maximum amount in PC motherboards which also have on-board network adapter. Thus, it is natural to think that high-end installations may include 6 cards. Then, there are also more exotic server boards with several PCI buses and they could take more than 6 cards which could also be considered.