多年以后，主唱David Lee Roth 在自传中揭示了这一无厘头条款的来由：Van Halen 乐队在当时是把大型摇滚现场演唱会推向高校及二／三线地区的先锋，由于常常会遇到没有处理过这种大场面的承办者，因此合同里有大量条款来确认演出承办者把场地，器材，工作人员安排等等细节都严格按要求准备好。合同里有成章成章的技术细节，包括场地的承重要求，各类出入口的宽度，电源要求，以至于插座的数量和插座之间的间隔。因此，乐队把棕色豆条款夹带在合同里，以确认承办方是否“仔仔细细阅读了所有条款”。David说：“如果我在后台的M&M里找到棕色豆，我就会立马知道承办方（十有八九）是没好好读完全部技术要求，我们肯定会碰上技术问题。某些技术问题绝对会毁了这场演出，甚至害死人。”
// kern/fs/vfs/inode.h
struct inode_ops {
unsigned long vop_magic;
int (*vop_open)(struct inode *node, uint32_t open_flags);
int (*vop_close)(struct inode *node);
int (*vop_read)(struct inode *node, struct iobuf *iob);
int (*vop_write)(struct inode *node, struct iobuf *iob);
int (*vop_fstat)(struct inode *node, struct stat *stat);
int (*vop_fsync)(struct inode *node);
int (*vop_namefile)(struct inode *node, struct iobuf *iob);
int (*vop_getdirentry)(struct inode *node, struct iobuf *iob);
int (*vop_reclaim)(struct inode *node);
int (*vop_gettype)(struct inode *node, uint32_t *type_store);
int (*vop_tryseek)(struct inode *node, off_t pos);
int (*vop_truncate)(struct inode *node, off_t len);
int (*vop_create)(struct inode *node, const char *name, bool excl, struct inode **node_store);
int (*vop_lookup)(struct inode *node, char *path, struct inode **node_store);
int (*vop_ioctl)(struct inode *node, int op, void *data);
};
/*
* Abstract operations on a inode.
*
* These are used in the form VOP_FOO(inode, args), which are macros
* that expands to inode->inode_ops->vop_foo(inode, args). The operations
* "foo" are:
*
* vop_open - Called on open() of a file. Can be used to
* reject illegal or undesired open modes. Note that
* various operations can be performed without the
* file actually being opened.
* The inode need not look at O_CREAT, O_EXCL, or
* O_TRUNC, as these are handled in the VFS layer.
*
* VOP_EACHOPEN should not be called directly from
* above the VFS layer - use vfs_open() to open inodes.
* This maintains the open count so VOP_LASTCLOSE can
* be called at the right time.
*
* vop_close - To be called on *last* close() of a file.
*
* VOP_LASTCLOSE should not be called directly from
* above the VFS layer - use vfs_close() to close
* inodes opened with vfs_open().
*
* vop_reclaim - Called when inode is no longer in use. Note that
* this may be substantially after vop_lastclose is
* called.
*
*****************************************
*
* vop_read - Read data from file to uio, at offset specified
* in the uio, updating uio_resid to reflect the
* amount read, and updating uio_offset to match.
* Not allowed on directories or symlinks.
*
* vop_getdirentry - Read a single filename from a directory into a
* uio, choosing what name based on the offset
* field in the uio, and updating that field.
* Unlike with I/O on regular files, the value of
* the offset field is not interpreted outside
* the filesystem and thus need not be a byte
* count. However, the uio_resid field should be
* handled in the normal fashion.
* On non-directory objects, return ENOTDIR.
*
* vop_write - Write data from uio to file at offset specified
* in the uio, updating uio_resid to reflect the
* amount written, and updating uio_offset to match.
* Not allowed on directories or symlinks.
*
* vop_ioctl - Perform ioctl operation OP on file using data
* DATA. The interpretation of the data is specific
* to each ioctl.
*
* vop_fstat -Return info about a file. The pointer is a
* pointer to struct stat; see stat.h.
*
* vop_gettype - Return type of file. The values for file types
* are in sfs.h.
*
* vop_tryseek - Check if seeking to the specified position within
* the file is legal. (For instance, all seeks
* are illegal on serial port devices, and seeks
* past EOF on files whose sizes are fixed may be
* as well.)
*
* vop_fsync - Force any dirty buffers associated with this file
* to stable storage.
*
* vop_truncate - Forcibly set size of file to the length passed
* in, discarding any excess blocks.
*
* vop_namefile - Compute pathname relative to filesystem root
* of the file and copy to the specified io buffer.
* Need not work on objects that are not
* directories.
*
*****************************************
*
* vop_creat - Create a regular file named NAME in the passed
* directory DIR. If boolean EXCL is true, fail if
* the file already exists; otherwise, use the
* existing file if there is one. Hand back the
* inode for the file as per vop_lookup.
*
*****************************************
*
* vop_lookup - Parse PATHNAME relative to the passed directory
* DIR, and hand back the inode for the file it
* refers to. May destroy PATHNAME. Should increment
* refcount on inode handed back.
*/