is there a role for software architectures

... space framework is C-based The I/O Kit maintains a database known as the I/O Catalog The I/O Catalog is a registry of all available I/O Kit classes Another database, the I/O Registry tracks object ... can run While it may seem reasonable and fair that each thread gets to run for an equal amount of time, this is impractical, as some threads have a greater need 23 CHAPTER  MAC OS X AND IOS for ... including Linux, have a design where the kernel’s address space is mapped into each task’s address space The kernel has 1GB of address space available, while a task has 3GB available When a task context...

Ngày tải lên: 15/03/2014, 02:20

... ACCESSBANK DATABANK DATABANK DATABANK DATABANK DATABANK DATABANK //DATABANK //DATABANK DATABANK ACCESSBANK The MSD class library transfers an entire sector of data (typically, 512 bytes) at a ... time For this reason, a sector size array is required in the MSD class firmware In PIC18 devices, the maximum data size that is allowed in a single bank of RAM is 256 bytes Data variables that are ... certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India The Company’s quality...

Ngày tải lên: 11/01/2016, 16:48

... more transactions Each transaction contains a token packet, a data packet, and a handshake packet (The handshake packet isn’t present in isochronous transfers.) Each packet begins with a packet ... NAND flash, which has fast erase and write times NAND flash also has lower power consumption and is much cheaper than NOR flash A CPU accesses NAND flash chips via data lines and command and address ... or a mini-B plug An example of a USB On-The-Go device is a camera that can function as a mass-storage device that stores images that PCs can access via USB and as a host that sends images to a...

Ngày tải lên: 06/07/2014, 15:37

... Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 Santa Clara Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509 Australia - ... count indicates that how many bytes were transferred A transfer of data from the Host to the Mass Storage Peripheral appears as Example EXAMPLE 1: MASS STORAGE DATA TRANSFER, PERIPHERAL TO HOST ... media interface layer The first is the initialization handler, which is called after the Peripheral has been enumerated and initialized by the Mass Storage client driver The initialization handler...

Ngày tải lên: 11/01/2016, 16:46

... require a constant data transfer rate For example, an Internet telephony application that carries a conversation in real time is a good candidate for isochronous transfer mode Isochronous data requires ... transfers Isochronous transfers provide guaranteed amounts of bandwidth and latency They are used for streaming data that is time-critical and error-tolerant or for real-time applications that ... guaranteed amounts of bandwidth and guaranteed maximum transmission times For isochronous transfers, timely data delivery is much more important than perfectly accurate or complete data transfer...

Ngày tải lên: 07/10/2013, 00:20

... USBInstallDriver should create an appropriate subkey for the driver by calling the RegisterClientSettings function so the next time that the USB device is attached, the USBD module can locate the ... prompting a user In some cases it may be necessary to specify the precedence order to a greater level of detail; for example, combining vendor- and device-class specifiers In these cases, the ... GroupX_ID values may be combined to generate other combinations The precedence for such combinations is as follows, in descending order: Group1_ID\Default\Default Group1_ID\Group2_ID\Default Default\Group2_ID\Default...

Ngày tải lên: 07/10/2013, 00:20

... Idle Handshake ACK ACK DATA0/ DATA0/ DATA1 DATA1 NAK DATA0 T/O STALL T/O ACK Idle Host Function There are Four Types of USB Transactions ? Isochronous (Audio, telephony …) –Periodic, Bounded latencies, ... –Stall conditions ? Special - PRE –Enables Hub for low speed communications A Typical USB Transaction Consists of Three Packets Idle Token IN DATA0/ DATA0/ Data DATA DATA SET OUT T/O NAK STALL ... –First packet in any transaction –Specifies function address, endpoint –Specifies data direction ? Data - DATA0, DATA1 –0 - 1023 bytes ? Handshake - ACK, NAK, STALL –Report status of data transaction...

Ngày tải lên: 13/12/2013, 00:15

... board (ME53) The software is available from the ADQ project Get the newer PCI versions of these Meilhaus boards and update the software Take any device that doesn’t work on Linux, but has a very ... meteorological field and satellite image display system, SAPO (http://sourceforge.net/projects/sapo), and the best available free numerical computer language to date, PDL (Perl Data Language) (http://pdl.perl.org/) ... Universidade de ?ora” for making this update possible Biography Xavier Calbet (/user/42" title="View user profile.): Xavier Calbet (xcalbet AT googlemail DOT com) is a long time free software user...

Ngày tải lên: 23/10/2013, 22:15

... board (ME53) The software is available from the ADQ project Get the newer PCI versions of these Meilhaus boards and update the software Take any device that doesn’t work on Linux, but has a very ... meteorological field and satellite image display system, SAPO (http://sourceforge.net/projects/sapo), and the best available free numerical computer language to date, PDL (Perl Data Language) (http://pdl.perl.org/) ... Universidade de ?ora” for making this update possible Biography Xavier Calbet (/user/42" title="View user profile.): Xavier Calbet (xcalbet AT googlemail DOT com) is a long time free software user...

Ngày tải lên: 13/12/2013, 11:15

... just data channels, which you can only access sequentially There exist, nonetheless, char devices that look like data areas, and you can move back and forth in them; for instance, this usually applies ... /dev as either a char device or a block device, the internal organization of the software is different [1]SCSI is an acronym for Small Computer Systems Interface; it is an established standard ... by mapping filenames and paths (as well as other information, such as access modes) to data structures stored in data blocks Such an interface is completely independent of the actual data transfer...

Ngày tải lên: 24/12/2013, 01:17

... programming and application programming is in how each environment handles faults: whereas a segmentation fault is harmless during application development and a debugger can always be used to trace ... that can be accessed by an application Modules can register many different types of facilities; for each facility, there is a specific kernel function that accomplishes this registration The arguments ... is concerned, the registry for I/O memory is accessed in the same way as for I/O ports, since they are actually based on the same internal mechanism To obtain and relinquish access to a certain...

Ngày tải lên: 24/12/2013, 01:17

... philosophical reason and a practical one Philosophically, it's always a bad idea to put arbitrary limits on data items being managed Practically, scull can be used to temporarily eat up your ... authorization for device access A scull_unload script is then available to clean up the /dev directory and remove the module As an alternative to using a pair of scripts for loading and unloading, ... The released source uses an array of 1000 pointers to areas of 4000 bytes We call each memory area a quantum and the array (or its length) a quantum set A scull device and its memory areas are shown...

Ngày tải lên: 24/12/2013, 01:17

... page for data transfer This limited the total size of a user file to KB (or whatever was appropriate for the host platform) The start argument is there to implement large data files, but it can ... serial line and a script that polls for status change An indispensable tool for these situations is the "magic SysRq key," which is available on more architectures in 2.2 and later kernels Magic ... next chapter, is a system call that acts on a file descriptor; it receives a number that identifies a command to be performed and (optionally) another argument, usually a pointer As an alternative...

Ngày tải lên: 24/12/2013, 01:17

... involves a data transfer The possible values are _IOC_NONE (no data transfer), _IOC_READ, _IOC_WRITE, and _IOC_READ | _IOC_WRITE (data is transferred both ways) Data transfer is seen from the application's ... normal operation This is only partly true for ttys Although a text display is meant to display only ASCII characters, sometimes control characters can slip through in the data being written and ... a process is put to sleep, how it is awakened, and how an application can ask if there is data without just blindly issuing a read call and blocking We then apply the same concepts to write As...

Ngày tải lên: 24/12/2013, 01:17

... function is called with the (unsigned long) data value DECLARE_TASKLET_DISABLED(name, function, data); Declares a tasklet as before, but its initial state is "disabled,'' meaning that it can be scheduled ... that a run is necessary; this is accomplished by "marking'' the bottom half In the case of tq_immediate, the necessary call is mark_bh(IMMEDIATE_BH) Be sure to call mark_bh after the task has ... humans or by the hardware One hundredth of a second is a suitable precision for human- related time intervals, while one millisecond is a long enough delay for hardware activities Although mdelay...

Ngày tải lên: 24/12/2013, 01:17

... advantage of this technique is that it makes available an area of consecutive physical memory that is suitable for DMA This is currently the only safe way in the standard kernel to allocate a buffer ... statistics on cache usage There is even a kernel configuration option that enables the collection of extra statistical information, but at a noticeable runtime cost Cache statistics may be obtained ... SLAB_HWCACHE_ALIGN This flag requires each data object to be aligned to a cache line; actual alignment depends on the cache layout of the host platform This is usually a good choice SLAB_CACHE_DMA This...

Ngày tải lên: 24/12/2013, 01:17

... overall system performance How I/O operations are performed on each platform is well described in the programmer's manual for each platform; those manuals are usually available for download as ... problem with hardware caching is the easiest to face: the underlying hardware is already configured (either automatically or by Linux initialization code) to disable any hardware cache when accessing ... on any Linux platform where you have access to a digital I/O interface that is accessible via outb and inb (even though the actual hardware is memory-mapped on all platforms but the x86) Later,...

Ngày tải lên: 24/12/2013, 01:17

... save_flags is a macro, and that it is passed the variable to hold the flags directly without an & operator There is also an important constraint on the use of these macros: save_flagsand restore_flags ... not safe with regard to sharing; ISA is edge triggered, because this signaling is easier to implement at hardware level and therefore was the common choice in the 1980s This issue is unrelated ... bit; such devices are a minority, although the parallel port is one of them For that reason, short does not have to clear such a bit A typical task for an interrupt handler is awakening processes...

Ngày tải lên: 24/12/2013, 01:17

... data items in addition to standardizing on a specific endianness Natural alignment means storing data items at an address that is a multiple of their size (for instance, 8-byte items go in an ... how alignment is enforced by the compiler, the dataalign program is distributed in the misc-progs directory of the sample code, and an equivalent kdataalign module is part of misc-modules This is ... dereferencing for architectures that permit you to access unaligned data #include list_add(struct list_head *new, struct list_head *head); list_add_tail(struct list_head *new, struct list_head...

Ngày tải lên: 24/12/2013, 01:17

... may have known about By placing a keep before any path directives, you can cause modprobe to add new paths to the list instead of replacing it alias alias_name real_name Causes modprobe to load ... data, which will almost always be THIS_MODULE; and data is a pointer to whatever data is to be shared Note the use of a const pointer for the data; it is assumed that it will be exported in a ... the module real_name when asked to load alias_name The alias name usually identifies a specific capability; it has values such as scsi_hostadapter, eth0, or sound This is the means by which generic...

Ngày tải lên: 21/01/2014, 07:20