Marco SRS Air Bag Suspension

Ram Remote Lock

Multiprocessor Semaphore

MULTIPROCESSOR SEMAPHORE

Abstract

=============================================

Shared memory semaphores are basic tools for interprocessor synchronization. Although

self-imposed design constraints can often reduce synchronization requirements, semaphores offer significant flexibility to multiprocessor system designers. The implementation presented here illustrates some fundamental issues of multiprocessor concurrency and demonstrates the tremendous value of a multitasking OS like DSP/BIOS.

Many variations on this theme are possible. Most obviously, we can modify the semaphore to handle multiple tasks on one processor or tasks on more than two processors. And because our wait operation handles notification interrupts and task wake-up, we can implement any scheduling policies that make sense for more generalized versions.

MULTIPROCESSOR SEMAPHORE

==============================================

Multiprocessing architectures are becoming pervasive. DSPs are widely used in dense multiprocessor arrangements at the network edge, and systems-on-chip often include DSP cores to accelerate math-intensive computation. Although DSP/BIOS provides a standard, efficient, robust API for uniprocessor applications, we sometimes encounter situations where interprocessor synchronization mechanisms would be very useful. Here we will take a look at multiprocessor mutual exclusion and we will talk about new method to implement interprocessor semaphores using DSP-BIOS.

Many multiprocessor DSP systems are designed to share a physical pool of memory in the sense that each processor sees the memory as directly addressable - a DSP shares a region of memory with a host processor or other DSPs-.

A common architecture uses a large region of single-port RAM shared by all devices, including the host. Although arbitration issues complicate hardware design. A second architecture uses of dual-port RAM between processors. The downside here is the relatively high cost and small storage capacity of these devices - large banks of expensive DPRAM are seldom practical. But in applications that use segmented data transport or small data sets where small amounts of DPRAM are sufficient, this method is very useful. DPRAM is relatively fast, designer-friendly and, unlike FIFOs, can store shared data structures used for interprocessor communication.

We need to remember this when using shared memory. When processors have on-chip cache or a system uses write posting, software designers must pay attention to shared variable coherence. Depending on the processor, programmers can disable cache, use cache by-pass, or flush cache to ensure that a shared location is in a proper state. The cache control API in TI's comprehensive Chip Support Library, for example, provides an ideal tool for cache subsystem management. Solutions to write-post delay problems are system-specific.

Our discussion here assumes that two processors use a common shared memory buffer to pass data or to operate cooperatively on a data set. In either case, one or more tasks on the processors might need to know the state of the buffer before accessing it, and possibly to block while the buffer is in use. As in the case of single-processor multitasking, we need a mutual exclusion mechanism to prevent inappropriate concurrent operations on the shared resource. Let's start with a quick review of mutual exclusion to better understand multiprocessor issues.

Shared resource management is a fundamental challenge of multitasking. A task (or thread, or process) needs the ability to execute sequences of instructions without interference so it can atomically manipulate shared data. These sequences, known as critical sections, are bracketed by entry and exit protocols that satisfy four properties - mutual exclusion, absence of deadlock, absence of unnecessary delay and eventual entry (no starvation). Our focus here is mutual exclusion - the remaining properties are detailed in any number of textbooks and will be satisfied by our multiprocessor semaphore.

Relative to a shared resource, mutual exclusion requires that only one task at a time execute in a critical section. Critical section entry and exit protocols use mechanisms such as polled flags (often called simple locks or spin locks) or more abstract entities such as blocking semaphores. Simple locks can be used to build protection mechanisms of greater complexity.

B-Semaphore

The semaphore is a system-level abstraction used for interprocess synchronization. It provides two atomic operations, wait (P) and signal (V), which are invoked to manipulate a non-negative integer within the semaphore data structure. The wait operation checks the value of the integer and either decrements it if positive or blocks the calling task. The signal operation either unblocks a task waiting on the semaphore or increments the semaphore if no tasks are waiting. A binary semaphore, with value limited to 0 and 1, can be used effectively by an application to guard critical sections.

A multiprocessor semaphore can be implemented by placing its data structure in shared memory and using RTOS services on each processor to handle blocking. Before outlining an implementation, let's look at two aspects of semaphores that cause complications in a multiprocessor environment. One is low-level mutual exclusion to protect shared data within a semaphore and the other is wake-up notification when a semaphore is released.

Low-level mutual exclusion

At its core, a semaphore has a count variable and possibly other data elements that must be manipulated atomically. System calls use simple mutual exclusion mechanisms to guard very short critical sections where the semaphore structure is accessed. This prevents incorrect results from concurrent modification of shared semaphore data.

In a uniprocessor environment, interrupt masking is a popular technique used to ensure that sequential operations occur without interference. Interrupts are disabled at the entrance to a critical section and re-enabled on exit. In a multiprocessor situation, however, this isn't an option. Even if one processor could disable the interrupts of another (rarely the case), the second processor would still execute an active thread and might inadvertently violate mutual exclusion requirements.

A second technique uses an atomic test-and-set (or similar) instruction to manipulate a variable. This variable might be the semaphore count itself or a simple lock used to guard critical sections where semaphore data is accessed. Either way, a specialized instruction guarantees atomic read-modify-write in a multitasking environment. Although this looks like a straightforward solution, test-and-set has disadvantages in both uniprocessor and multiprocessor scenarios. One drawback is dependence on machine instructions. These vary across processors, provide only a small number of atomic operations and are sometimes unavailable. A second problem is bus locking. If multiple processors share a common bus that doesn't support locking during test-and-set, processors might interleave accesses to a shared variable at the bus level while executing seemingly atomic test-and-set instructions. And a third problem is test-and-set behavior in multi-port RAM systems. Even if all buses can be locked, simultaneous test-and-set sequences at different ports might produce overlapped accesses.

Now consider two approaches that are very useful in shared memory scenarios. One relies on simple atomic hardware locks and the other is a general-purpose software solution known as Peterson's algorithm.

Hardware flags

In shared memory systems, hardware-assisted mutual exclusion can be implemented with special bit flags found in multi-port RAMs. DPRAM logic prevents overlap of concurrent operations on these hardware flags, forcing them to maintain correct state during simultaneous accesses. And because processors use standard-issue read/write instructions to manipulate the flags, special test-and-set-like instructions are not required. But this is still a limited solution - software engineers often encounter shared memory systems that lack this feature. So let's take one more step to arrive at a general-purpose hardware-independent method.

Peterson's Algorithm

Peterson's algorithm, published in 1981, provides an elegant software solution to the n-process critical section problem and has two distinct advantages over test-and-set spin locks. One is that atomic test-and-set is not required - the algorithm eliminates the need for special instructions and bus locking. The other is eventual entry - a task waiting for entry to a critical section won't starve in a weakly fair (typical) scheduling environment. Although Peterson's algorithm looks deceptively simple, it's a culmination of many attempts by researchers to solve the critical section problem.

The following pseudo-code shows the entry and exit protocols used to enforce two-process mutual exclusion. Note that Peterson adds a secondary "turn" variable - this prevents incorrect results from race conditions and also ensures that each waiting task will eventually enter the critical section.

Listing 1: Peterson's Algorithm

initialization

P1_wants_entry = P2_wants_entry = FALSE

turn = P1

task P1

P1_wants_entry = TRUE /* set lock */

turn = P2 /* grant turn to other task */

loop while (P2_wants_entry and turn == P2) /* buzz waiting for lock */

critical section /* execute critical section */

P1_wants_entry = FALSE /* release lock */

task P2 /* same logic as P1 */

P2_wants_entry = TRUE

turn = P1

loop while (P1_wants_entry and turn == P1)

critical section

P2_wants_entry = FALSE

We can easily imagine situations where more than two processes try to enter their critical sections concurrently. Peterson's algorithm can be generalized to n processes and used to enforce mutual exclusion between more than two tasks. And other n-process solutions, such as the bakery algorithm, are readily available in computer science textbooks. Our discussion here is limited to the two-process case only for clarity and brevity. Pseudo-code for the n-process Peterson algorithm can be found on the Electric Sand web-site.

Blocking mechanism

Now that we have a low-level mutual exclusion tool to safely manipulate shared data within a semaphore, consider the other key ingredient of semaphores, blocking. Assuming that each processor runs DSP/BIOS or another multitasking OS, we develop our wait operation using services that are already available on each individual processor. DSP/BIOS provides a flexible semaphore module (SEM) that we use in our implementation.

When the owner of a uniprocessor semaphore releases it with a signal system call, the local scheduler has immediate knowledge of the signal event and can unblock a task waiting on the semaphore. In contrast, a multiprocessor semaphore implies that the owner and the requestor can reside on different processors. Because a remote kernel has no implicit knowledge of signal calls to a local kernel, the remote kernel needs timely notification of local signal events. Our solution uses interprocessor interrupts to notify other processors of local activity involving a shared semaphore.

Semaphore implementation

This implementation of a multiprocessor binary semaphore (MBS) assumes that the hardware supports interprocessor interrupts and that a task won't try to acquire a semaphore while another task on the same processor owns it. The latter restriction simplifies the example and can easily be removed with some additional design work.

The wait operation

MBS_wait is invoked to acquire a shared memory semaphore. If the semaphore is available, MBS_wait decrements it and continues. If the semaphore is already owned, the requestor task blocks within MBS_wait until a release notification interrupt makes it ready-to-run. Once the interrupt occurs and higher priority tasks have relinquished the CPU, the task waiting on the semaphore wakes up within MBS_wait and loops to re-test it. Note that the task doesn't assume ownership immediately when unblocked. Because a remote task might re-acquire the semaphore by time the requestor wakes up, MBS_wait loops to compete for the semaphore again.

When MBS_wait determines that a semaphore is unavailable, it sets a notification request flag in the shared semaphore data structure to indicate that the processor should be interrupted when the semaphore is released elsewhere in the system. To avoid a race condition known as the lost wake-up problem, MBS_wait atomically tests the semaphore and sets the notification request flag if the semaphore is unavailable.

Code for the wait operation is divided into two distinct parts. MBS_wait contains the blocking code and is called by an application. MBS_interrupt runs in response to the notification interrupt and posts a local signal to the task waiting on the semaphore. This is very similar to a device driver model, where the upper part of a driver suspends a task pending I/O service and the interrupt-driven lower part wakes it up.

The signal operation

MBS_signal releases a semaphore by incrementing its value and posting an interrupt to a processor that requested release notification. This causes MBS_interrupt to execute on the remote processor where a task is blocked on the semaphore. Note that this varies slightly from the uniprocessor signal operation described earlier where the semaphore is incremented only if no tasks are blocked.

Pseudo-code

Now that we have a notion of shared semaphore architecture, let's look at pseudo-code describing the wait and signal operations. Keep in mind that this example applies to a two-processor version where only one task at a time on each processor tries to acquire the semaphore. General implementations servicing more processors and sharing the semaphore between multiple tasks on each processor can be implemented by using the n-process Peterson algorithm and modifying the MBS operations.

Note that the critical sections, enforced by Peterson's algorithm (Peterson entry and Peterson exit), are very short instruction sequences used to manipulate the semaphore data structure. The details of Peterson's algorithm are not shown - these are implicit in the Peterson entry/exit operations. The lock and turn variables used in Peterson's algorithm are distinct from the semaphore data elements accessed in the critical sections.

The critical sections are preceded with DSP/BIOS TSK_disable calls to prevent task switching. A task switch during a critical section could cause another processor to spin indefinitely in Peterson entry if it tries to acquire the same semaphore. The critical sections should be executed as quickly as possible.

Also note that the example omits error checking, return values and timeouts. The pseudo-code is meant to highlight discussion topics rather than provide a detailed implementation template.

MBS_wait () {

success = FALSE /* local variable, not part of semaphore */

while (success == FALSE) { /* repeat semaphore acquisition attempt */

TSK_disable () /* prevent DSP/BIOS task switch */

Peterson entry /* Peterson's entry protocol */

/* critical section begins */

if (sem_value > 1) {

sem_value = sem_value - 1

success = TRUE

}

else {

notification_request = TRUE

}

Peterson exit /* end critical section */

TSK_enable () /* re-enable DSP/BIOS scheduler */

if (success == FALSE) { /* local variable shows result */

SEM_pend () /* sleep using DSP/BIOS semaphore */

}

}

}

MBS_interrrupt {

SEM_post () /* local wake-up signal using DSP/BIOS */

}

MBS_post () { /* release the semaphore */

TSK_disable ()

Peterson entry

/* start critical section */

sem_value = sem_value +1; /* increment the semaphore */

if (notification_request == TRUE) { /* notify a remote task? */

send notification interrupt /* yes - send an interrupt */

}

Peterson exit /* end critical section */

TSK_enable ()

}

==============================================

About the Author

Dr.Wael AlBayaydh has has been working in information technology for several years, concentrating on areas such as operating system, networking, electronic commerce, Internet services, LDAP and Web servers. AlBayaydh has authored a number of articles for some publications, and he presents his own papers at industry conferences. He can be reached at wr_y@hotmail.com

Remote for XA201/601 Lock $13.99 Xena Remote for XA201/601 Lock

Car Remote Lock $10 Car Remote Lock

Ram Mount / RAM Mount Base Suction Mount Twist Lock - Requires RAM Cradle / RAM-B-166U $36.86 Ram Mount - RAM Mount Base Suction Mount Twist Lock - Requires RAM Cradle - RAM-B-166U

2002-2007 Dodge Ram 1500 Tailgate Lock Pop & Lock Dodge Tailgate Lock PL8340 $85.73 pop lock power tailgate lock black the power lock electric tailgate lock mounts quickly and permanently inside the tailgate and ties easily into the existing power door lock or remote entry system lock your doors and the tailgate automatically locks with them a raised lock for easy operation they are side mounted to the tailgate handle for an oem look made from hardened stainless steel easy installation no drilling required. auto parts warehouse has extensive pop lock tailgate lock catalogs.we are now offering free shipping on all pop lock tailgate lock orders over $50.00. our secure pop lock tailgate lock catalog is available every hour of everyday. shop with confidence for all your pop lock tailgate lock needs. pop lock tailgate lock are in stock and available today. save upto 60% off dealer price on your next pop lock tailgate lock purchase. our online catalog contains a wide selection of the oem and aftermarket parts you need at unbeatable prices

Ram Mount / RAM Mount Twist Lock Suction Cup Base w/Universal X-Grip II / RAM-B-166-UN8U $59.44 Ram Mount - RAM Mount Twist Lock Suction Cup Base w/Universal X-Grip II - RAM-B-166-UN8U

Ram Mount / RAM Mount Universal X-Grip Holder Twist Lock Suction Cup Mount / RAM-B-166-UN7 $55.34 Ram Mount - RAM Mount Universal X-Grip Holder Twist Lock Suction Cup Mount - RAM-B-166-UN7

Ram Mount / RAM Mount Locking Apple iPad w/Twist Lock Suction Cup Mount / RAM-B-166-APL8U $71.23 Ram Mount - RAM Mount Locking Apple iPad w/Twist Lock Suction Cup Mount - RAM-B-166-APL8U

2002-2007 Dodge Ram 1500 Tailgate Lock Pop & Lock Dodge Tailgate Lock PL8340 02 03 04 05 06 07 $95.44 POP & LOCK POWER TAILGATE LOCK, BLACK -- The Power Lock Electric Tailgate Lock Mounts Quickly And Permanently Inside The Tailgate And Ties Easily Into The Existing Power Door Lock Or Remote Entry System, Lock Your Doors, And The Tailgate Automatically Locks With Them, A Raised Lock For Easy Operation, They Are Side Mounted To The Tailgate Handle For An OEM Look, Made From Hardened Stainless Steel, Easy Installation, No Drilling Required. Auto Parts Warehouse has extensive Pop & Lock Tailgate Lock catalogs.We are now offering FREE shipping on all Pop & Lock Tailgate Lock orders over $50.00. Our secure pop & lock tailgate lock catalog is available every hour of everyday. Shop with confidence for all your pop & lock tailgate lock needs. Pop & Lock Tailgate Lock are In Stock and available today. Save up to 60% off dealer price on your next Pop & Lock Tailgate Lock purchase. Our online catalog contains a wide selection of the OEM and aftermarket parts you need at unbeatable prices

Mobile Dock With Lock by RAM Mounts - Docking station $305.99 Motion Mobile Dock With Lock by RAM Mounts - Docking station - for C5 C5v F5 F5v

Ram Mount / RAM Mount Tab-Tite iPad / HP TouchPad Cradle Twist Lock Suction Cup Mount / RAM-B-166-TAB3U $55.62 Ram Mount - RAM Mount Tab-Tite iPad / HP TouchPad Cradle Twist Lock Suction Cup Mount - RAM-B-166-TAB3U

Ram Mount / RAM Mount 3.25" Diameter Suction Cup Twist Lock Mount w/1" Ball / RAM-B-224-1U $24.14 Ram Mount - RAM Mount 3.25" Diameter Suction Cup Twist Lock Mount w/1" Ball - RAM-B-224-1U

Ram Mount / RAM Mount 3.3" Suction Cup Base w/Twist Lock / RAP-224-1U $17.46 Ram Mount - RAM Mount 3.3" Suction Cup Base w/Twist Lock - RAP-224-1U

Ram Mount Base Suction Mount Twist Lock (RAM CRADLE REQUIRED) $31.44 NOTE: This listing is for a RAM base only. You must add a cradle for your specific unit, listed under the "Accessories" tab, to complete your mounting system! The RAM-B-166U, twist lock suction cup mount consists of a 3.25" suction cup locking base and diamond plate end. The mount is designed with a

Remote Control RF Deadbolt Keyless Lock $230 No Keys Needed w/ The Remote Control RF Deadbolt Keyless Lock Single Push Button Remote Entry Up To 30 ft. Away No External Wiring Required - Easy Installation Under 10 Minutes 100% Bump Resistant Deadbolt Protection� Battery Operated - 6 Month Battery Life� One-Touch Entry W/ Remote Control Technology And Deadbolt Strength The Remote Control RF Deadbolt Keyless Lock gives your home superior deadbolt protection with one-touch keyless entry. When your hands are full, simply press the button on the remote control and open your door up to 30 feet away from any direction. This battery powered lock installs in under 10 minutes and requires no additional wiring or drilling. No need for keys or codes with this remote control operated keyless lock . Get unsurpassed ease of entry and deadbolt protection with The Remote Control RF Deadbolt Keyless Lock. Reliable Radio Frequency Deadbolt Protection - Increased Safety And Usability Keyless lock technology offers unsurpassed ease of entry with the strongest deadbolt protection available. With built-in backup features such as 2 additional keys for conventional operation and a panic exit function that allows you to exit your home from the inside without the remote control, you get all the security features of a regular deadbolt with improved keyless functionality and ease. This keyless lock uses radio frequency technology, so you don't even have to aim the remote control at the lock to open/close it. Your entire family can take advantage of this technology, which comes standard with two remote control but accepts up to 30. Complete with anti-scan code hopping and deadbolt capabilities, no unauthorized guests will be able to enter your home. Features: One button remote control entry Easily open the door when your hands are full with the press of a button Convenient for kids or people with arthritis or disabilities� Requires no additional wiring, 10 minute installation Battery operated with a 6 month battery life Comes standard with 2 remotes, accepts up to 30 Stylish and secure Includes: 1 Deadbolt Lock 5 Tumbler pins 2 Remote Control 2 Keys (5-Pin SC Type Keyway)

Ram Mount Ram Anchor Line Lock Chock W/Post $36.75 Anchor Line Lock Chock With Post Features: Material: High Strength Plastic Ball Size: 1. 5 Color: Black.

Pop and Lock Tailgate Lock $51.95 The Pop & Lock Tailgate Lock is the only one on the market that requires no tools or drilling of holes for installation. It simply Bolts on to the handle and locks in place, securing the tail gate and its contents when used with a cap or tonneau. Made of hardened steel, the Tailgate Lock is finished with a UV resistant coating, giving it a stock appearance. All Pop & Lock products emphasize simplicity of design and function, and are manufactured from austempered - both hard and malleable - steel. This combination cannot be surpassed in an anti-theft device.   Kit Includes: Tailgate lock Keys Mounting hardware Easy to read instructions   Applications: Year Make/Model Black Part No. Price 88-98 Chevy CK & GMC Sierra XXXPL1050 $51.95 99-Up Chevy Silverado/GMC Sierra XXXPL1100 $51.95 94-03 Chevy S-10/GMC Sonoma XXXPL1600 $51.95 96-Up Isuze Hombre XXXPL1600 $51.95 87-96 Ford F150 XXXPL2310 $56.95 87-98 Ford F250/F350 XXXPL2310 $56.95 93-Up Ford Ranger XXXPL2310 $56.95 04-Up Ford Ranger XXXPL2310 $56.95 94-Up Mazda B Series XXXPL2310 $56.95 97-03 Ford F150 (Select Models) XXXPL2500 $52.95 99-Up Ford F250/F350 XXXPL2500 $52.95 94-01 Dodge Ram 1500 XXXPL3300 $51.95 94-02 Dodge Ram 2500/3500 XXXPL3300 $51.95 02-Up Dodge Ram 1500 XXXPL3400 $56.95 03-Up Dodge Ram 2500/3500 XXXPL3400 $56.95 97-Up Dodge Dakota XXXPL3600 $51.95 86-Up Nissan (except Titan) XXXPL4000 $51.95 95-04 Toyota Tacoma XXXPL5100 $51.95 05-Up Toyota Tacoma XXXPL5200 $61.95 05-Up Toyota Tacoma (Compartment Lock) XXXPL5220 $101.95 05-Up Toyota Tacoma (Compartment & Tailgate Lock) XXXPL5221 $161.95 05-Up Honda Ridgeline XXXPL6000 $81.95

Hydraulic RAM $70.1 High Quality Content by WIKIPEDIA articles A hydraulic ram, or hydram, is a cyclic water pump powered by hydropower. It functions as a hydraulic transformer that takes in water at one hydraulic head (pressure) and flowrate, and outputs water at a higher hydraulichead and lower flowrate. The device utilizes the water hammer effect to develop pressure that allows a portion of the input water that powers the pump to be lifted to a point higher than where the water originally started. The hydraulic ram is sometimes used in remote areas, where there is both a source of lowhead hydropower, and a need for pumping water to a destination higher in elevation than the source. In this situation, the ram is often useful, since it requires no outside source of power other than the kinetic energy of water. Author: Miller, Frederic P./ Vandome, Agnes F./ McBrewster, John Binding Type: Paperback Number of Pages: 84 Publication Date: 2010/07/28 Language: English Dimensions: 5.98 x 9.01 x 0.20 inches

RAM Mount RAP2241U RAM Mount 3.3 .in Suction Cup Base with Twist Lock $24.79 RAM 3.3 Diameter Suction Cup Base with Twist Lock The RAP2241U suction cup twist lock base contains a standard RAM double hole diamond shaped end. The 3.3 diameter suction cup is designed to have an extra strong hold on any smooth nonporous surface but for best result mount the suction cup on a glass surface. The diamond shaped end has two holes 1.912 from center to center. This will connect to RAMB238 Diamond Plates Series the universal industry standard AMPS hole pattern or directly to the back of the RAM Composite HOL Cradles. This suction base DOES NOT have a RAM 1 rubber connection ball. Material: High Strength Composite Ball Size: 1 Rubber Ball B Size

Roll??N??Lock Retractable Tonneau Covers - Electric [94-01 Dodge Ram SB] $1431 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply."

Roll??N??Lock Retractable Tonneau Covers - Electric [94-01 Dodge Ram LB] $1528 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply."

Roll??N??Lock Retractable Tonneau Covers - Electric [02 Dodge Ram 2500/3500 LB] $1528 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply."

Roll??N??Lock Retractable Tonneau Covers - Electric [03-08 Dodge Ram 1500-3500 LB] $1528 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply. OE tailgate cap must be replaced with aftermarket tailgate cap provided with system."

Roll??N??Lock Retractable Tonneau Covers - Electric [02 Dodge Ram 2500/3500 SB] $1431 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply."

Roll??N??Lock Retractable Tonneau Covers - Electric [03-08 Dodge Ram 1500-3500 SB] $1528 "Convenient remote control. Fast opening electric motor overtorsion-spring drive system. Handy built-in cargo light. Lowest-profile aluminum housing - only 7??"" deep. Patented emergency ?Ç£Drive Converter?Ç¥ allows the operator to instantly convert electric drive to manual with the flip of lever. Built-in tailgate locking feature.;;Uses additional flanges (included) that screw or clamp to the inside edge of the OE bed rails. Allow additional 15 min. for installation. Ships in two boxes. Additional shipping charges may apply. OE tailgate cap must be replaced with aftermarket tailgate cap provided with system."

Venom Creeper Remote Diff Lock Kit with Servo VNPTCR192 $43.02 This is the Remote Diff Lock Kit w/Servo for the Venom Creeper R/C Rock Crawler. High quality components. Satisfaction ensured. Constructed from the finest materials.

1994-2001 Dodge Ram 1500 Tailgate Lock Pop & Lock Dodge Tailgate Lock PL3300 $43.33 pop lock manual tailgate lock black pop lock is the only tailgate lock that requires no truck modification effective security against tailgate theft protects the contents inside a tonneau cover or camper top and also guards against theft of the tailgate itself the taillights or bed extender for your truck made of top quality armored steel and have a raised lock for easy operation they are side mounted to the tailgate handle for an oem look. auto parts warehouse has extensive pop lock tailgate lock catalogs.we are now offering free shipping on all pop lock tailgate lock orders over $50.00. our secure pop lock tailgate lock catalog is available every hour of everyday. shop with confidence for all your pop lock tailgate lock needs. pop lock tailgate lock are in stock and available today. save upto 60% off dealer price on your next pop lock tailgate lock purchase. our online catalog contains a wide selection of the oem and aftermarket parts you need at unbeatable prices

Streetwise CLA08R Portable Car Lock Alarm with Remote $59.27 The patented design of the SWAT LOCKR not only protects your car with an ear piercing siren it also locks the steering wheel in place to prevent potential car thieves from turning the wheel. It is equipped with four theftdeterrent features: a warning LED a flashing strobe light a120 db siren and a hard steel lock. This alarm locks to the steering wheel in less than 10 seconds no need to run wires or pay for expensive installation. Three keys are included for unlocking the alarm and you can set your own remote control code. When the window is disturbed by tapping or other significant jolt the alarm will sound and a LED light flashes for 30 seconds. If no other disturbance occurs the alarm resets itself. If the disturbance continues the alarm will continue for another 30 seconds until the disturbance ends or the alarm unit is disarmed. The alarm unit requires two (2) 9volt batteries (not included). The IR remote requires 1 12volt battery (included). The alarm measures 14 and onehalf inches by 7 and threequarters. This alarm has a 1 year warranty.

Option Racing Fuel Door - Chrome w/ Lock [94-01 Ram] $150 Option Racing Fuel Door - Chrome w/ Lock

Pace Edwards Tailgate Locks - Pop & Lock [94-01 Dodge Ram] $27.51 Pace Edwards Tailgate Locks - Pop & Lock

Pilot Fuel Door - w/ Lock (Chrome) [02-Up Dodge Ram] $85.59 Pilot Fuel Door - w/ Lock (Chrome)

Pilot Fuel Door - w/ Lock (Chrome) [94-01 Dodge Ram] $85.59 Pilot Fuel Door - w/ Lock (Chrome)

Kershaw Ram, Serrated, Ram $99.95 Smooth & easy one handed ambidextrous index-finger opening with flipper system or thumb-knobs. Patent pending Hawk-Lock is both secure and easy to operate G-10 handle overlays front & back. Reversible/removable pocket clip includes a wheel-lock that secures and seats the clip while in your pocket. SPECIFICATIONS: - Blade Length: 3. 125 foot - Length Closed: 4. 375 foot - Overall Length: 7. 5 foot - Weight: 3. 8 oz. - Blade Style: Modified Clip Point - Blade Finish: Matte - Edge: Partially Serrated - Blade Steel: Sandvik 13C26 - Rockwell Hardness: 56-58 - Locking Mechanism: Hawk Lock - Handle Material: 410 Stainless Steel with Black G-10 Overlays - Fittings: Stainless Steel - Pocket Clip: R/H or L/H, Tip Up

Pace Edwards Tailgate Locks - Pop & Lock [02 Dodge Ram 2500 / Ram 3500] $27.51 Pace Edwards Tailgate Locks - Pop & Lock

Pace Edwards Tailgate Locks - Pop & Lock [02 Dodge Ram 1500;;03-05 Dodge Ram] $30.02 Pace Edwards Tailgate Locks - Pop & Lock

Security Lock $10 The cheapest way to protect you phone against theft is the smart way: choose Security Lock! This protection app will guard your phone in three valuable ways. One: a lock code, to stop curious friends or enemies. Two: an alarm that can be turned on from a distance and expose the thief. Three: a remote information wipe command to defend your valuable information if your phone is lost. And your special bonus feature: password protected storage for confidential data. Security lock: Be smart. Be safe.

Nikon MC-30 Camera Remote Cord. $54.99 Attachment: 10 pole.Length: 80cm Nikon Remote cord MC-30 For F5/F90X enables remote firing of a camera with trigger-lock function.EAN/Barcode 2000110668419.Free delivery by post.

Kershaw R.A.M. R.A.M. $99.95 The new R. A. M. Offers a choice of smooth and easy, one-handed opening systems. The knife user can open the R. A. M. With an ambidextrous flipper system or the built-in thumb knobs. The flipper system incorporates resistance to hold the blade securely in the closed position until deployed by pulling on the extended tang at the front of the spine. The award-winning knife also features the patent-pending Hawk Lock that is both secure and easy to operate. The knife offers Sandvik 13C26 stainless steel blades and an anodized aluminum handle with G-10 overlays for a secure grip.